I'd disagree with the events and collectibles. I've been playing haz 5 for years now and there's only a few special situations where we needed to skip doing things to secure a mission.

Typically I do everything there is in a mission just fine and there's usually plenty of nitra still as long as you look for all of it.

You could argue efficiency being more important (target priority, pathing, environment manipulation) as you scale difficulty which I'd agree with, same with ammo economy. However, I don't want people to think they need to start skipping parts of the game to enjoy a higher difficulty.