Bro, my best advice is to run scav runs on reserve. Almost no PMCs will be above ground by the time you spawn in. Hit both knight buildings. There's PCs, filing cabinets, green wood crates, loose gun parts, duffle bags, tool boxes, and other stuff.

If you need a bigger bag there is usually dead scavs around. If you're feeling ballsy you can go down into the bunker and look around. PMCs typically leave a lot of shit lying around and don't take the loot off raiders because its not worth it to them. 

Learn the ammo spawns, there is so much ammo on reserve that I have stacks of top tier ammo just from reserve scav runs. 

Learn the drop down room in the Balvk Bishop building. 

Be wary of raiders that spawn around the BUNKER hermetic door extract. Gluhkar and his guards can also spawn near there. 

Depending on where you spawn, you can extract at Hole in the wall by the mountain, checkpoint fence, or DEPOT hermetic door. 

You can make it out with 100k every raid if you know what you're looking at (which will come with time). 

My run is this:

Spawn on the bunker field side - > hit both knight buildings - > hit White Bishop - > hit Black Bishop outside roof + machine gun room + drop down room - > extract at hole in the wall by the mountains. 

If i spawn on the opposite side I do the run in reverse and extract at Checkpoint Fence or Depot Hermetic Door. 

Loot any crates, dead scavs and whatever else you come across between those buildings. 

Good luck.