How do I win on Forbidden?

Feel like every time I play a solo forbidden I encounter the same things.

AI ignoring enemies just to heat seek me and expose my location the millisecond a player gets close, despite the other player making all the noise.
Players sitting in corners not moving until you walk into their line of sight.
T6 4man squads throwing 30 nades at any noise they hear.

I'm trying to learn but I don't really see anything to learn from these encounters. Am I supposed to just sit still for the entire raid and pray?

Also - where the fuck are the reds? I've hit over 30 safes today and I'm getting shit like 10k koen and a PSU or space boy comic. Not a single raid has been fun when I don't even get a chance to shoot back.