On the harder difficulties, and on boss bots raiders, rogues they are allowed to aim for your head. These guys don't mess around, they can land those shots 250+ metres away.
For each bot type just change this:
botTable['pmcbot'].difficulty.easy.Aiming['AIMING_TYPE'] = 4;
botTable['pmcbot'].difficulty.normal.Aiming['AIMING_TYPE'] = 4;
botTable['pmcbot'].difficulty.hard.Aiming['AIMING_TYPE'] = 4;
botTable['pmcbot'].difficulty.impossible.Aiming['AIMING_TYPE'] = 4;
Where 'pmcbot' changes for each bot type that exists, just change aiming type to 4 so that they are only allowed to aim for your body.
Even if you lie down they won't hit your head and instead find a way to aim for your body instead no matter the angle.
Another alternative is to leave bot settings and instead use headshot direction, that way you can take "headshots" but you won't die from one shot head-eyes from out of nowhere.
Just different approaches to find a good game play challenge you enjoy especially now that SAIN isn't getting ported to 3.11
The problem now is that AI can see you through bushes, so we need a solution for that.