Something I noticed during my time at Amazon - overly nit picky code review comments.
Once code is submitted for review, it’s too late in the development cycle to be demanding refactors and nit picking the quality of the code. That should all be handled by linting. You can make those comments but in my opinion they should all be informational only to help the developer to make changes for their NEXT code change.
The only changes that should be required during a code review should be around the functionality of the code, making sure it doesn’t break anything and it properly implements the feature. Every other comment should be optional.
I saw too many instances of a junior engineer submitting a pull request, getting blasted with comments about their code quality, and then the PR sitting in review for days or even weeks while they address the comments. In an ideal world this would be fine, but developers are human, and nobody wants to see their work get criticized and have to basically redo all of their work because a senior developer has strong opinions about what is “good code”.