It depends if you are new to the game or not. There’s two big categories of mods - those that only perform modernization and quality of life features, and those that rework everything until it looks like Skyrim.
If you are new, I’d recommend not using any of the latter; they can be fun, but it’s good to know New Vegas “as is”, I’d say. Otherwise the selection is so big it’s hard to pick, I’m running like 30 or so (mostly extra weapons, enhanced AI, better crafting, extra sidequests and a player home). But just give an idea on the scope of mods, the settlement building system in FO4 was inspired by mods originally in New Vegas (Real Time Settler and Wasteland Defense), so there’s really a wide scope of things to pick from.
As for the former, there’s some that jump to mind - NVAC (New Vegas Anti-Crash), FNV 4GB memory patcher, stutter remover, nevada skies and/or EVE (essential visual enhacements), and probably a texture pack or two to enhance visuals. Maybe even NVSE, which is a scripting extension mod that other mods can/will need.
Fallout New Vegas (with some mods), Vampire Bloodlines (with community patch) and Deus Ex Human Revolutions. I’d personally even put Deus Ex 1 there for the story itself, but the game is pretty old and may be jarring for modern audience even with mods…
I design and operate monitoring systems, and let me tell you, information fatigue is a real thing. Warning labels make sense when sensibly used; otherwise people get conditioned to ignore them, even if they would be crucial. Think of road signs: if there was a speed limit of 10 before every turn, all speed limits would soon lose credibility.
Hardest part of the job is actually learning which alerts we need to keep and which to trim… if we simply slap warnings on everything, everyone would ignore them soon enough.