> just aim for 100% test coverage instead (with excluding some categories of files).

That's where the 'gaming' comes in.

The tests start just going through lines without hitting a single expect statement.

The ignore files start becoming battlegrounds in the PRs because people just exclude half the damn project.

We just have a simple rule... if you wrote code, you have to write coverage for it. If it breaks and your test doesn't catch the breakage, the bug fix goes back to you. Some people will ask "but what about what I'm working on now", you'll have to communicate that you feel your previous work was far more important.