Personally I would be careful in assessing a driver that is quick on either W10 or W11. It seems those car are easier to drive and easier to extract its maximum performance. When someone like Hulk, although experienced, but they put him immediately on the hot seat and still perform decently + Russell, although very talented, but still he is coming from a different car with different controls and everything, still able to match and even exceed Bottas, I have no doubt that the car itself might have flatter the driver.
I actually think Vettel will do great on Aston. If he has a car that easy to drive, thus he can do whatever he wants with the car, he should be able to extract the maximum performance of that car. I actually won't be surprised if Vettel perform better on RP vs Perez.
This doesn't mean Perez is slow tho, but I don't think he would trouble Ver. At best, it would be like Ham vs Bot, where Bottas is actually close to Lewis most of the times, also behind most of the times. At worst, he would perform like Gasly, Albon, or Kvyat during their RB stint. I think he would be closer to Ver, but still not close enough to trouble Mercs like what Ver want from Perez.
Of course that is just my speculation. I have a feeling that RB is actually a difficult car to drive and with Perez I hope I can see whether the problem is with the car or the driver. Do we have a situation like in Honda MotoGP bike where basically only a single person can ride it fast? Currently on the grid, I feel like only Ham, Ric, Alo, and maybe Leclerc that can drive a difficult car without a lengthy adjustment period. That doesn't mean that other driver can't drive as fast as them. Like I've said before, I think Vettel can do great on Aston. Also a driver like Ric, although I rate him high in terms of adaptability, especially in driving a difficult car, I don't think he has the ultimate pace as the other driver I mentioned.
Having said all of that, if Perez does ended up close (or on par/better) to Ver, then you really need to put question mark on Gas, Alb, Kvyat, and basically their driver academy program.
Other than that, I really hope Tsunoda won't disappoint. And I hope someone can challenge Mercs at the start of the season.