I mean, from my point of view, Elizabeth as a Goddess is at the tier of the Four Archangels minimum, or even higher than them,
(TL.DR AT BOTTOM) since:
-Considering the fact that wings express power, and how they are consistent in that fashion with the hierarchy of the Goddess Clan (e.g Supreme Goddess = biggest wings. Fodder = baby wings). Elizabeth should be at the tier of the Four Archangels. Surprisingly enough, the nanatsu no taizai wiki has this under the ability section of the Goddess Elizabeth:
'' As stated a Goddesses' strength is measured by the number of wings and their sizes and Elizabeth has four wings and their size surpasses even Ludociel of the Archangels showing to be more powerful. '' (http://nanatsu-no-taizai.wikia.com/wiki/Elizabeth_(Goddess) ). So yeah, looking at wings only and ignoring everything else, Elizabeth should be stronger than Ludoshel in terms of PL wise and is only inferior to Mael with sunshine (which is natural). If you discount the graces, Elizabeth should be the strongest Goddess, second to her mother.
-She's the daughter of the Supreme Goddess, WHICH has to account for something, It's not just a coincidence that Zeldris and Meliodas happen to be the top tiers of their clan, and are also the sons of the Demon King.
-Goddess Elizabeth literally stood in front of half the Ten Commandment brigade (6 of them IIRC?) and uttered the statement that she would fight all of them by herself in the moment if they happened to go after Meliodas. Considering how Galan, with the
truth commandment was standing there, what Elizabeth saying must have been the truth, that she would be able to go up against 6 of the ten commandments (who happen to be around 30-50k ranges), or at the minimum, Elizabeth herself believed it to be the truth. Since Elizabeth isn't this cocky warrior who overestimates her own strength, and even pulls away from conflict at all costs in almost all situations and has the confidence to understand the limitations of her own power, what she said is quite believable. Sure, there's the possibility that she was wrong, or she possibly might've had divine protection (from her mother against the commandments) to shield her from the truth commandment, explaining why some of the commandment members never trusted her negotiation, despite Galan's commandment presence. But in the likelihood, it's more believable that Elizabeth did have the power to defeat 6 of the Ten Commandments who were present there, since some of them were not battle types (e.g Merascylla) or were mere replacements (e.g Fraudrin) or just merely weak (e.g Galan). The strongest individuals there, were Monspeet and Derriere, and even Ludoshel in a 1v6 could destroy them all IMO unless Indura happened.
-Considering how all of the Four Archangels at one point or another, have praised Elizabeth's power (ark) or have asked for her assistance, makes me to believe that she has to be at their level at a minimum, and possibly higher. After all, why would you ask and consistently praise someone's power who was notably weaker than yourself? Hell, Ludoshel who pretty much despises Elizabeth's personality and ideals of peace and tranquillity, has yet to ever disrespect her power. In fact, he was more confident
when Elizabeth was by his side against the Indura, than when Sariel and Tarmiel were. Consequently, he even asked Elizabeth for her power, and was glad for her appearance, stating that if they combined their powers, they would be able to eliminate the Indura, and considering how Ludoshel's ark individually did nothing, implies that Elizabeth's ark would've made up for his weakness or inability to affect the Indura individually, I actually believe this, considering Elizabeth's magic individually placed the Indura's so close to being purified and defeated, but with a mere small power boost from Sariel/Tarmiel, Elizabeth easily purified them after. So a combination of Elizabeth and Ludoshel's ark when being used offensively, would've definitely eliminated the Indura.
-Elizabeth's full release of her magic literally illuminated the entire battlefield, pushed everyone back (who was close), and made the Indura's pay attention to Elizabeth, given their facial expression and ''!!!!!'' at her magic being released.
Why is this downplayed? Ludoshel's full magic power never did this. Granted, he didn't put his 100% into one magic spell, but his ark at full power with consecutive blasts didn't scratch Derriere, or even make her pay as close attention to him. Hell, she even allowed multiple of his blasts to make contact against her, something the Indura definitely did not allow Elizabeth to do once her drills of light made contact, as seen by their immediate resistance to her light.
-From an individual stand point,
Elizabeth performed better against the Indura's than the Four Archangels, despite her being in a 1v2 instead of a 3v2. Sure, Elizabeth failed to purify them and would've been pushed back entirely and followed up on by them after (which would've been devastating for Elizabeth), but given the fact that she was in a 1v2 battle, and was able to fend off the demons who just fodderized the Four Archangels, the strongest military force of the Goddess Clan, is nothing short of impressive. Hell, even Tarmiel said that it's not surprising that she is struggling, considering the Indura just took down 3 of the Four Archangels, and I'm sure we can all agree that 3 angels together are superior to Elizabeth's power individually. If you look even more closely as well, Elizabeth practically
saved Sariel, Tarmiel and arguably Ludoshel from certain death. Monspeet basically one-shotted Sariel and Tarmiel, who were on the ground unable to heal themselves due to his tentacles holding on to them, and Derriere was able to individually fodderize Ludoshel in Phase 1. And this was all whilst the angels had the numbers advantage against the demons. But Elizabeth stepping in, means Sariel and Tarmiel were able to heal (since Elizabeth pushed Monspeet away and his grip on the angels) and stopping Ludoshel from having to fight Derriere, which is a death sentence alone, never mind Monspeet as well (lol).
Why is this also downplayed and ignored? Elizabeth saves Sariel, Tarmiel and Ludoshel from certain death from demons who to me, seem only inferior to Assault Meliodas, all whilst placing them on the threshold of being purified and consequentially defeated in a 1v2, yet no one acknowledges or praises her for that, but are immediately ready to jump on the bandwagon on how Elizabeth ''always'' needs protection from literally anything (lol) or how she needled to be bubbled when she was knocked unconscious from being off-guard. Are you guys being wilfully ignorant? 
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She stood in front of the Supreme Goddess and the Demon King in battle and was apparently able to keep up with Meliodas in his AA tier form. Granted, we didn't see the full battle, but considering that Meliodas in his 90-100k AA tier form is being significantly pressured, bloody, bruised, and on the verge of death from the looks of it and Elizabeth is in the same state of health as he is, implies she's somewhere near that level, otherwise, Elizabeth would've already been on the floor and most likely dead if it takes just a 50k basic demonic punch to take her down

. Either way, I think we should consider this moment, as not everybody can stand in front of the 2 Gods of this series and not be fodderized immediately, even if they were holding back drastically. But, I'm fine to leave this point out when arguing for Elizabeth, since we have yet to see the full battle (Nakaba please, I want to see the Gods fodderize their children... would've been lovely to see

) and have only small clips of the fight. Still though, this should be taken into small consideration if you're saying she's weak or strong.
-Elizabeth's feats dictate that her magic is considerably stronger than the Four Archangels, since her ark has had more effectiveness, versatility and praise than anyone else in the clan. She can heal better, purify better, summon biblical animals and even offensively hurt people better from the feats we've seen with Elizabeth in comparison to the Four Archangels. Though, in feats, the angels naturally outclass her in durability, speed, and other physical capabilities since their graces improve those areas of power + I imagine magic is her speciality and since she's less of a warrior - has less refined physical skills.
TL.DR - Elizabeth's wings dictate she is AA tier, or specifically above Ludoshel and only inferior to a Mael with sunshine, especially if you consider she is the only daughter of the Supreme Goddess. Elizabeth stood in front of 6 commandments (in 30-50k ranges) and threatened to fight them, which is strange for someone who doesn't want to fight usually, so it has to prove Elizabeth is capable of doing that. The Four Archangels have praised or asked for Elizabeth's power more times than they have with each other. Elizabeth's full magic release is something none of the other angels have done, and with that she performed significantly better individually against the Indura and ended up saving Sariel, Tarmiel and Ludoshel from certain death. Stood in front of the Gods and wasn't fodderized immediately and is comparable to AA tier Meliodas, and by feats, has significantly stronger magic (ark) to the Four Archangels, and consequentially anybody else in the clan, but comes short in physical capabilities.
Just quote the TL.DR if you want to respond and not read the entire post