RPG overhaul or difficulty mod.
I've been playing on a new modlist for a week now, after finishing KCD2, and I've just about reached a stable game. I'll post it soon.
If you want to grab something immediately:
HARDCORE22V2 COMPLETE- REALISTIC COMBAT OVERHAUL:
https://www.nexusmods.com/cyberpunk2077/mods/12569
Arasaka Mech Health fix for (HARDCORE22V2 COMPLETE- REALISTIC COMBAT OVERHAUL):
https://www.nexusmods.com/cyberpunk2077/mods/16998
Enemies of Night City:
https://www.nexusmods.com/cyberpunk2077/mods/8467
And their dependencies, in the "Requirements" section.
If you are into "basic needs" immersive stuff you can add:
Dark Future - Urban Survival Gameplay:
https://www.nexusmods.com/cyberpunk2077/mods/16300
Dark Future realistic carry capacity:
https://www.nexusmods.com/cyberpunk2077/mods/19242
But then you better get the ability to buy stuff from any vendor:
https://www.nexusmods.com/cyberpunk2077/mods/2894
And then why not actually watch an animation as you are eating when at restaurants:
https://www.nexusmods.com/cyberpunk2077/mods/7322
Once you take the immersion rabbit hole, you are better off going all in, with a bunch of other mods I'll list later.
There isn't much ambiguity about gameplay altering mods because there are not that many big rebalances. Other mods that are interesting but won't be compatible with the above are:
Wannabe Edgerunner - A simple Cyberpsychosis mod:
https://www.nexusmods.com/cyberpunk2077/mods/5646 (CDPR practically copied this mod with some changes into their v2.0 but it still exists and makes additions on top of that)
Lifepath Bonuses and Gang-Corp Traits:
https://www.nexusmods.com/cyberpunk2077/mods/2217 (I did a v1.6 playthrough with it and it's a great faction overhaul, but it would be incompatible with Enemies of Night City and I wanted to try that one this time)
The Gangs of Night City:
https://www.nexusmods.com/cyberpunk2077/mods/7233 (I'm a bit wary of mods that have heavy scripting like adding radiant quests and membership in gangs and such, so if I experiment with this it will be after I'm sure the game is already stable)
If you go the way of mods that add scripted systems and systems-driven gameplay, you might also try They Will Remember, Immersive Fixers, Fighting Gangs Allowed (Reasonable Police), NIGHT CITY ALIVE, and others such as those that add "jobs". The problem with these is that they all have heavy scripting and the more complex, the more likely to be unstable, and the problems might only surface after lots of hours sunk.
In my experience some of the best gameplay changes come from QoL mods, where you install it and you find you can't live without it. The game was absolutely a turd if unmodded pre-2.0, now I can't say if it's all that bad unmodded, but mods certainly have a lot to offer in terms of gameplay improvements.