So lets start with the basics against Reinhard. Vegeta is way faster and stronger then reinhard, which makes a normal fight between those two quite onesided. (I think most will agree on this)
It comes all down to Reinhards hax. Then it will get interesting. Vegetas attacks are not only on a godly level, but can destroy everything, that isnt immortal(hakai).
Hakai just for your information is the following:
Beerus says the technique fully removes matter from existence, and a powerful energy is released when the object disappears. Obviously, this is because all matter is meant to simply distribute elsewhere when its original form is dismantles, but that does not appear to be the case with Hakai.
So if reinhard would be desintegrated with hakai, he wouldnt be able to resurrect thanks to his phoenixblessing. The question here is, can Vegeta actually hit him with hakai, since reinhards power are completly bullshit in that regard. The answer is: Yes. There are multiple ways.
In general: authorities > blessings. So if Hakai is comparable to an autority there isnt anything reinhard can do to avoid it, even his sword(which he will have access too) cant do anything against „destroy all matter“, since it will be destroyed too(my standpoint is, because it is blessed by the swordgod, its also a blessing).
But lets say we let it slide and say „ok, the sword can cancel this“. What happens next? Well the best thing about vegeta in this tournament is:
He is aware, that he is in a manga/anime. So when facing against reinhard he will get aware that his powers are bullshit and related to the system of a videogame. He knows the concept of videogames thanks to his son trunks, who likes to play these. (And even plays some himself, check youtube for „vegeta plays“)
So if reinhard hax cancels out, all his attacks he will come to the conclusion, that this is probably a videogame and therefore tries to overload it…. By blowing up everything, since then he doesnt need to hold back to save earth.
Does Vegeta have power to destroy everything? Yes. He is even listed as a: multi-galaxy destroyer power level in the battlewiki. So if he decides to blow up the entire re.zero universe(with his gods too) he can do it.
In this way reinhard would probably survive once due his phoenixblessings, but then dies in the void of space. If he cant get anymore blessings(i dont think the universe of his manga can withstand the pure destruction that vegeta can do). Even if he wished beforehand for a blessing of spacebreathing, he is done, because vegeta can always sense him and erase him then from existence.
Also note that a Super Saiyajin God can survive in space.
So my arguments are:
Hakai trumps his blessings. They are a gift from god, but not godly in itself, since it manifests as an ability of his own.
If they dont belong to himself, vegeta can actually counter them with his forced spirit fission.
„Forced Spirit Fission allows the user to separate and manipulate energy from their target, granting them the ability to do things such as undo
Fusion or
Absorption techniques and free trapped souls.“
Which would deattach the blessings from reinhard by itself. In eitherway, they would be countered.
If we assume hakai(spriti fission gets countered, he notices the hax/bullshit and realizes he is played in another mangauniverse and destroys this universe by its core. Which will we lead to his win in the end anyway thanks to his extremly destructive potential.