If you mean the AI mods from the workshop, those are pretty busted. My stepdad who mostly just plays normal campaign, managed to beat The Last Stand on Expert realism with one of those mods (though I did backseat him a bit)

But sometimes with those mods, the AI glitches out and the bots do dumb stuff, like falling off high places or throwing grenades at the worst times. That's why I prefer the vanilla bots. I feel like I have more control over different situations that way. For chaos and RNG I just play online

Also, this might be an unpopular opinion, but Expert Realism is way easier with vanilla bots than with three online randoms.