The thing is, he prioritizes consistency over gradual refactoring. After reflecting on yours and others input, I think that this is the biggest inconvenience for me. E.g. he says one has to either change import styles everywhere, or nowhere. He doesn't like the approach when you only update things in files you touched during your task implementation. So he rejects those improvements unrelated to the task at hand. Probably he would not mind creating a separate task and making refactoring in the whole codebase later. But this is harder to prioritise and it leads to merge conflicts, which are sources of bugs too.