I had a necro playthrough but not too focussed on daedra or Oblivion. I had this house mod tracked for a long time, you could give it a shot (https://www.nexusmods.com/skyrimspecialedition/mods/41257).

I remember seeing some vigilants fighting a xivilai in the wild, probably a feature of enhanced encounters mod, you could look into that and maybe increase the spawn chance.

With a quick search found this: https://www.nexusmods.com/skyrimspecialedition/mods/4593 It has been last updated in 2016 so be aware. Mihail and 4thunknown have some daedra creature mods you could look into (goat-monster and daedroth to name a few). As for armour there is a large quantity you can choose from (keywords: daedra, molag, necromancer)

After more search:

Spell texture replacer: https://www.nexusmods.com/skyrimspecialedition/mods/6359?tab=description

Building: https://www.nexusmods.com/skyrimspecialedition/mods/50933

Armour: https://www.nexusmods.com/skyrimspecialedition/mods/58895 https://www.nexusmods.com/skyrimspecialedition/mods/58192 https://www.nexusmods.com/skyrimspecialedition/mods/36577 https://www.nexusmods.com/skyrimspecialedition/mods/38201

Quest: https://www.nexusmods.com/skyrimspecialedition/mods/34457

Creatures: Daedroth titans, Ruinachs, Banekins, Ogrim by Mihail and https://www.nexusmods.com/skyrimspecialedition/mods/15831