On my team, the level of scrutiny a merge request receives depends on the author and the functionality. MRs from a principal or lead engineer tend to get rubber-stamped at a higher rate, though, to your point, many of us will explicitly call out code that we would like to have reviewed in more detail. If a more junior level developer submits a merge request, it is highly likely their code will get a close review.

I'm not sure I agree with your premise that code reviews are the product of a culture with a lack of trust and ownership. I think, in fact, submitting to a review process is a sign of ownership -- it's saying "hey, the quality of the code we produce as a team is important to me, and I know I make mistakes."