> These "seniors" lack even the most basic understanding of the shit they're using, but feel the need to impose their opinions about libraries, tooling and languages constantly.

Oh yeah, I feel this. The problem is many "seniors" went from junior->senior by being the big fish in a small pond (small startup + golfing buddies with the CTO) so they never had to question their own assumptions. Then they just glide from job to job at the senior level. It makes for monsters who can't differentiate their own personal preferences from industry best practices, and will attack your PRs if you go against either.