Difficult people are not “assholes”. Someone saying “your engineering practices are shoddy and the quality of your code is bad” does not make them an asshole. It makes them french maybe.

My point is that there are people low on the agreeableness scale, and they can often be exceptional engineers. You have to manage them, yes, but taking the easy way out of “i’ll sack anyone who’s prickly” will mean a shit team. You need people (or at least one), who will say “that won’t work because…” “this is bad because…” “this will fail because…”.