Thanks for the reply, I never really considered the the boss spawns not counting towards the overall AI count. I've temporarily removed SWAG and currently using SVM to manage bots, pmcs and bosses etc. so I'll remove the boss spawn from streets and give it another try.
Frankly never crossed my mind to try that - I just went to the center and killed as many guards as I could before going to other areas and my fps skyrocketed from 40-50 in that area to 70-80+. Did that a few times. I have a decent system as well [7700 @5.45GHz and a 7800xt plus lots of ram] so it's not a hardware issue.
For the record the area I am talking about is the Lexos area where the minefields are marked on Prim. avenue.