hi, welcome to the forum!
first - please be careful about modding.
the game is still regularly updated, outdated mods are then bound to cause issues.
as a rule of thumb - anything that uses an esp or a bsa (that is most mods) needs to be adjusted to Enderal / Enderal SE.
mods that only use textures or meshes are generally ok. general interface mods should also work (stuff like RaceMenu and iHud)
it reads as if you didn't play the game yet. please try playing without mods first - it's not vanilla Skyrim

apart from the assets the team created themselves a bunch of mods are already included - see the credits.txt in the gamefolder.
there's this
user curated list, and Nexusmods has a page dedicated to
Enderal SE.
it's modmanager Vortex supports the game, so could could use that.
note!
don't know about LOOT, but going with the SSE setting would probably be safe.
specifics:
- ENBs that are not made for Enderal SE
can break scenes. a popular one for the classic version was "
Rudy ENB" I don't know if an SE version of it exists.
(and I'm not sure if Classic <-> SE Versions of ENBs are interchangeable, probably not)
- SkyUI is already included (if playing on ultrawide you may need a
patch )
- i don't know of environmental overhauls for Enderal (game's been out for four years and no one deemed them necessary

)
hope that helps for now,
have fun!
edit!
it apparently uses Skyrim SE's ini files, that should be fixed with the next (Vortex) patch though