This includes never using mods which only increase damage / limb damage, or armor, or crit chance, or crit damage, or headshot damage. And this includes upgrading items, too, as upgrading only increase some stats (numbers).
And most importantly, this also includes any perks and cyberware which only increase some stat / number. I.e., perks / 'ware only increasing some sort of damage? Nope! Perks / 'ware only increasing armor? Nope! Perks / 'ware only increasing health? Things only giving extra movement speed? Nope, nope! Etc etc. Get ma drift?
But things which allow some new ability / feature? Those are a go. Immunities, guerilla hands to rip those fences off, silencers if desired, scopes, double jump legs, etc - all things which allow to "do something different / new" is a go.
This way, we don't limit ourselves from using any and all mechanics the game has to offer, but severaly reduce "OP" factor late-game. Further, we even start to use mechanics which were simply not needed before, simply 'cause we were nuking things left and right with no need to get any tactical / smart about it.