@Sirdanest OK, so
This one to make combat responsive. Enemies will visibly react to getting shot, instead of just continuing to fire at you as if nothing was happening. Works for the player as well, forcing you to find cover.
https://www.nexusmods.com/newvegas/mods/66646
This one to improve the way NPCs fight. They'll look for cover, attack you from longer distances, be more responsive to your actions, etc
https://www.nexusmods.com/newvegas/mods/58431
These two for overheating and recoil respectively, so that weapons feel more like weapons.
https://www.nexusmods.com/newvegas/mods/49892
https://www.nexusmods.com/newvegas/mods/61973
This one for realistic damage (the second one is an update). Damage becomes more significant, making the game more of a real fight and less of a battle of statistics. No longer enemies taking 20 shots to the head and continuing like nothing happened. I recommend the alternative version.
https://www.nexusmods.com/newvegas/mods/35335
https://www.nexusmods.com/newvegas/mods/54936
This so that NPCs can miss, otherwise you'll find drugged up ghouls sniping you from 100 meters away, and with the modded damage mechanics, that can be a problem. The default version tends to make every single character shoot like they're drunk, (like 2:00 am, bachelor's party drunk), so you may want to try the medium accuracy one, or the high accuracy one, if you like the challenge.
https://www.nexusmods.com/newvegas/mods/65817?tab=description
This one is a bit gory (or, very gory actually), but realistic. NPC react to their limbs being crippled, falling to the ground and crawling, or panicking.
https://www.nexusmods.com/newvegas/mods/67147
This one to make armor more significant, because you shouldn't be able to kill someone clad in power armor with a 9mm pistol.
https://www.nexusmods.com/newvegas/mods/63860
And yeah, that's about as good as it gets.