"Needs service" is the same as reporting that it is broken. Another thing is that warranty covers manufacturing defects so, for example, it is unreasonable to automatically void warranty for a screen just because the battery was replaced.
I get where you are coming from but this isn't so cut and dried, as incompetent repairs are certainly capable of damaging or destroying other components. Someone I know once unknowingly messed up an antenna in the process of replacing a phone battery with an after market one, which caused all sorts of odd and intermittent symptoms with communication issues. Why should a manufacturer be expected to deal with that under warranty?
Part of the problem with consumer electronics is that they aren't really particularly designed to be serviceable, let alone user-serviceable. So it's not like a car manufacturer saying they'll refuse to warranty a rear shock because you changed your own oil or whatever.
I'm a strong supporter of right-to-repair, but I'm not convinced that should extend to forcing user serviceable designs where there is an actual design tradeoff. On the other hand this is pretty hard to prove - maybe all you can do is go after user-hostile design changes that serve no other purpose.