Why can't I seem to grasp PvP tarkov

I'm 500 hours in and I simply can't compete in large map raids, put me in a small map like factory or labs and I'm an absolute chad.

In arena even I top frag half my games with a 3.2kd and I feel like I'm confident in that end, but when you put me in interchange or some big map I'll die to someone I don't see or someone that just knows where to rush spawns and I'll die 3 times in a row before doing one quest. This game is so unbelievably frustrating at times and I'm wondering when it gets easier.