-Then there's no need to foreshadow Elizabeth proving Sariel's statement less than perfectly accurate. Even though her claim that she would stop Mael can fit in as foreshadowing.
-Because, as you said, they're
both villains and one of them suffices in completely overwhelming 1/2 the Sin squad, you're basically expecting more of an asspull from characters who've so far been portrayed as weaker(raw power and ability wise) than Elizabeth's original form than her truly acting like a member of said team. That actually implies bias against her rather than a fair/objective perspective.
- Ban stealing raw strength to get Maelstarossa in the others' manageable range would only manage to completely wreck the writing choice Nakaba made with DayScanor VS AM Meliodas. It'd be senseless for Ban alone to bridge the enormous gap implied in the synopsis of this chapter. Escanor's involvement would damage even more the opinion on Nakaba's writing. Do you you really only expect the guys to be allowed the "invincible" tag and do you have an issue with women(at least that's what I glean from you missing the fact that even my data below the avi says I'm a "she", not a "he" so "she" will be getting on your case if you give "her" the reasons to)?!
-Those skills do portray her as far more versatile, even in activity, than a healer, no matter how hard you hide your head in the sand. Her actions, ever since the beginning, have portrayed her as more than a healer, she didn't heal against Ruin, she broke the enchantment, she didn't only heal against Hendy, she dispelled Dark Nebula which would've killed hundreds of people and wounded to some extent the very villain, she didn't heal against the Indura in the chapter that states from its mere title that she
fought them and she proved to be more resilient in a 1 VS 2 when aware of conflict than each of the DD when trying to 1VS 1 or 2 VS 1 Indura, besides, she purified, not merely healed them; she didn't just heal Ban or Diane at Corrand, she purified the human souls' grudge on Helbram and the "intruders" and took away almost all of Melascula's "toys", hard earned toys; she didn't just heal the S&D army against the demon one, she used whatever type of brainwashing skill she has to try and pacify the demons; she didn't just heal Guila when "Estarossa" attacked, she repelled him and purified one of his attacks that could've harmed the S&D squad once Diane exhausted her energy. Aside from Mel VS Escanor, there isn't 1 major conflict where she was present that would have her act as only healer or simply TnJ her way out of it.
-I've listed 6 skills and only 1 skill is directed towards healing; the argument above also tells you you're the one with a skewed vision of her portrayal, she loves preserving life which in essence should be a staple of her clan, given the main uses of Ark; but that doesn't mean she was only shown healing, or that that's her go to tactic, you can't "heal" opponents out of a conflict. She's not portrayed as a standard fighter, and she's not portrayed as a standard healer, this story doesn't actually have black and white angles, when will you learn that?! Ocean and Tornado would only give her the edge to go near Maelstarossa's and 5 C Mel's range, minus the bloodlust and their typical tactics; when did I say she hypothetically got Sunshine and Flash as well?!
-Gowther Sr and Gowther Jr have recently proved the physical gods aren't "invincible" in this universe, how would Elizabeth with even her mom's status(as SD) be that?! How would Mel as DK?! How would The One with 1/4 or one temporary hax ability of 1 of the "gods"?! And I was actually being modest by going as far as her getting 1/2 of the Graces, from the souls of the AAs that died next to her
or being released by mommy from her curse to be able to eventually reach and maintain the form and power level we got to glimpse when she cast the huge triskele in 208.

-That's what I was asking, when was the SD ever portrayed as a fighter by career
and not a fantasy parallel to a horrible political leader with too much power on their hands? Ludociel himself implies over and over that Elizabeth has the power to fight and vanquish the demons, Sariel himself said even royal demons would naturally be vulnerable to her Ark, the GC wants her to fight the demons and they're only miffed with her refusing to kill, not her being unable to, which means that we've been getting numerous pieces of foreshadowing that she's supposed to be on par with the 2 dudes you don't mind having immense power cause they're villains; especially since we've been told over and over that she was the only individual who's ever made a strong impression on both of them aside from the "gods".
- According to the fact that Gowther Jr helped his daddy accomplish a relative peace for Britannia with what they pulled and how Merlin was "mourning" Arthur, yes, their codes go quite close to Elizabeth's. There's a small difference there, but Junior seems to be trying to pull a self-sacrificing Elizabeth this chapter, and even Merlin's cryptic chat with Ellie in the chapter they were trying to awaken Arthur implied she wanted a safer, peaceful world to live in and Ellie may have promised her that once upon a time. And recently Arthur did.
-She was less vulnerable when casting HA on the 2 Indura than the Dynamic Duo when engaging them separately or 2 VS Induraspeet. The Derrieri off-guard punch doesn't hold unless you want me claiming that human Elizabeth can 1 VS 1 142k PL Mel.
-The difference is that Elizabeth would focus on helping to stop people like Maelstarossa and 5 C Mel(especially Mel), she wouldn't start clearing the board cause she has nothing better to do. She would focus on the matters that others can't handle or solo, like aoe healing her people or making good of Ban's effort of retrieving Mel's emotions by "persuading" one way or another, 5C Mel to accept his emotions back. She needs her own power to be able to get to him and interact long enough with him to manage that instead of getting knocked out or placed in a "protective" PoD bubble by the moron. You need to read the recent arcs, she's been more "out of distress" than "in" since her awakening and the flashback arc, she wasn't in distress for 1 moment against the army she "converted", she was the main "damage" dealer against the Indura and simply needed added team members, not an actual rescue, she was an equally losing opponent VS the SD & DK as Mel was, she was the one saving the team at Corrand from Mera's nasty tricks with the souls or saving Elaine from certain death since the others seemed to not know how to permanently stop her without killing her; she saved her team from certain death at Chandler's hands, just as much as Glo & Droll did; she staved off Mel's regression and truly dispelled his AM, she saved herself from Mel's stupid domineering 'tude and made her way to the Sins, the Chandler Clones situation is nothing compared to the previous circumstances; she saved the S& D squad from Estarossa's rage when the AAs constantly failed or were disinterested to, so...check again! She's been doing tons of things besides healing or being endangered and not at all by merely talking, so, so much for "she's a healer" or "damsel in distress" staple!

-Hmm, no, they are both equally important and you've got no argument to persuade me of the opposite;
-No, she said she will "stop" him, not chat with him and have a friendly farewell.
1) Only healing on Elizabeth's part won't either;
2)Yes, you are claiming the same Sariel is wrong in thinking and stating that he needs forgiveness from the SD for failing to
protect Elizabeth, not just saving Mael; by extension, you're claiming Sariel is wrong in thinking she's still very important to the SD;
3) She purified the grudging souls at Corrand with Hikari Are, not a chat;
4)She's kept her existing and able to reconnect with her original identity, albeit in an extremely cruel way, and the SD's generals/officers seem to believe, despite different personal opinions on her, that the SD wants her back essentially in the same way the DK wants Mel, only the goddesses aren't trying to brainwash or anything direct on Elizabeth. The methods differ, the intention's the same. And now, more than ever, the GC side in the war is in a pinch, Mael has resurfaced corrupted by the DK's power and the SD might not have a direct way to change that; the DD is gone from the picture for what seems like a long while; she technically only has one AA left to fight precisely for her; without BoB/CH Stigma and the Sins are loyal to Elizabeth, not the SD; how do you know she won't try anything to bridge the rift she put between herself and her daughter to save face and her situation?!