The phrase "I'm reviewing your pull requests" makes you sound pretentious on a literal level.

What do you mean by reviewing other people's PR when most of them are more senior than you?

I'm just kidding.

To be fair, I think taking away the pressure of "I have to review your PR to decide if your code should go to prod" off your shoulder can make you a lot more productive; it gives you more patience to understand parts of the codebase you haven't touched / seen, it helps you ask better questions rather than nitpicking on syntax, and it helps giving you more assurance to verify "these changes are legit, I can take the blame if shit goes wrong in prod".

Before reviewing a PR itself, I usually ask myself:

Should I be reviewing this PR?

Why is it "me" who should be reviewing this PR?

Do I have expertise in the stuff I'm about to review?

What value do I provide other than giving them a green tick?

Which parts of this PR should I be responsible of reviewing, while I let other experts review stuff that…