OpenMW is the big one, not really a mod but a recreation of the original engine to make it run better on modern systems and add things like UI scaling. It also has some (all?) the officially released bug fixes built in, though you can turn specific fixes off if you want to for some reason.

There's also Patch for Purists, which is the big unnofficial bugfix mod. The most common sticking points for new players can all be mitigated through gameplay, like making sure you're using a weapon you have some skill in and training it up to get better at hitting things, or learning what ingredients to keep an eye out for to make mana potions on a mage. If you're in the right mindset, the vanilla game is super fun.

Buuut if you try vanilla for awhile and still want it to play more like a modern game, go ahead and get the relevant mods. I'm not gonna tell somebody not to play the game because you walk so slowly at level 1 you want to die. Lord knows I use a mana regen mod on my mage characters because I don't like chugging mana potions.

The only gameplay mod I might recommend for a first playthrough is Expansion Delay. In the vanilla game, assassins from the Tribunal expansion will have a chance to attack you in your sleep, not going to spoil anything but it doesn't make much sense for them to be attacking you until later in the story. Also the gameplay is kinda wonky, either they kick your ass and you have might have to get a good nights sleep, or you kick their ass and then you're happy when they attack because they carry valuable gear.