Same honestly, I've only used it for one playthrough but it was really nice! It's one I'll have to go back to for sure. :)
KiaraRedVA
Oh boy, I have a lot that I tend to use, it depends on the playthrough but I do have a small stock of player homes I keep for any playthrough occasion!
This part of the list is some of my more favorite player house mods that I've used often.
Leaf Rest SSE by Aukmat/mnikjom Side note about this one, to get the key you may need to TCL into the mailbox.
Cynn's Honeyside Redone by Cynndal
Cynn's Vlindrel Hall by Cynndal
Assassin's Sanctuary by K13RAN64 It's not subtle, but sometimes you just need an edgy manor house.
~Honorable Mentions~
These are my less-used player homes I have but ones I still adore regardless.
Crypt of the Old Guard by ToggleAI
Unique Vampire Dens by Gonkish
The Northern Star Retreat Revised by ArchimageKhan
I have a couple more but this is already a pretty long list, I was also going to add Tel Jerdein but saw you already had it mentioned as well. :)
The only reason I ever tried out new land/quest mods, follower mods, and mods that added in random npcs, is because in one of my early save games I killed most of the townspeople and wanted to go to another land that was more populated/re-populate Skyrim with new NPCs because I ended up regretting killing so many people, but I didn't want to restart the save.
Oh, and also I don't think Nazeem is that bad. I don't like him but he's made to be that way anyways. Honestly, the worst punishment is to keep that guy alive, he'll always be wondering if his end is close every time you pass him, as many others have done to him.
Flashing Savegames Fix was already mentioned, so instead I'll offer up Main Font Replacement, I use the Magic Cards font and it's one of the mods I always use but always underappreciate.
You also mentioned a music mod, while it doesn't replace the main menu theme and it's not technically a UI mod, I always play with Celtic Music in Skyrim, all tracks are from Adrian von Ziegler I think!
Font Replacer: https://www.nexusmods.com/skyrimspecialedition/mods/14356 Celtic Music in Skyrim: https://www.nexusmods.com/skyrimspecialedition/mods/2980
FINALLY! My immersion is sated!
My favorite one was the immersive anxiety mod.
Oh I feel this. There's been playthroughs I've started purely to be evil, yet I still end up feeling bad most of the time.
I think the only run through I've had where I actually felt like I did a good job "justifying" it was with my very old Nerevarine Telvanni Sheogorath-worshipping sorceress that I played through Morrowind-Oblivion-Skyrim with. In her case, she wasn't trying to be necessarily evil, she was just blunt, had little patience, was straight to the point and didn't consider how her words or actions may affect someone, as long as she could continue hoarding artifacts and doing nutso mage things, she was happy. She also didn't understand why murder and thievery were illegal, if she saw something she wanted, she took it, she didn't get why the guards would be upset over it and was usually disgruntled with Skyrim's law system.
You mentioned Narfi, and that's one I remember giving a justification for on that play through. In my sorceress's mind, he deserved to be in a better place more suited for him, like the Shivering Isles, so off she sent him via a Lightning Bolt to the face.
I don't have any mod recommendations, but I wanted to give an example of how I justified it myself. I didn't feel as bad as I usually did with prior evil play throughs. :)
Well first off, I'm gonna miss my favorite nerdy subreddits. r/wow, r/Morrowind, r/Oblivion, r/Skyrim, r/Elderscrolls, and even r/trueSTL. Happy that Skyrimmods is here though!
Aside from that though, r/botchedsurgeries, r/amitheasshole, and r/hobbydrama.
The rest would be various animal subs, but hopefully, they find new homes quickly.
I had sort of the same problem when modding my summoner/sorcerer playthrough a while back, a lot of Necromancy stuff but not as much for the Daedric side of things. Now I love me some Necromancy, but it was a little frustrating not being able to find as much love for Daedra.
Someone else could probably recommend better as my recommendations here primarily come down to spell mods, but you mentioned a scholarly interest so something I can recommend is the Spell Research mod. I can't remember much about it as I haven't played with it enabled for a while, but it adds something extra rather than just getting spell tomes the normal way.
You already mentioned Mihails mods but I did the same, just added as many Daedra as I possibly could.
Not really Daedric-themed but this one adds more immersion to the College of Winterhold and lets you do quests for every school of magic, College of Winterhold Quest Expansion.
I might be able to recommend some house mods but the ones I used on my summoner playthrough were Dunmer-themed, and I think I just ended up using JK's College of Winterhold at the end of it.
Spell Research: https://www.nexusmods.com/skyrimspecialedition/mods/20983
College of Winterhold Quest Expansion: https://www.nexusmods.com/skyrimspecialedition/mods/66666
JK's College of Winterhold: https://www.nexusmods.com/skyrimspecialedition/mods/65676
Edit OH I also forgot, just for the scholarly side of things there's The Eloquent Reader, gives you some speech experience for reading books. https://www.nexusmods.com/skyrimspecialedition/mods/16338
Thanks for giving her a go! I'm very passionate about Skyrim modding so I'm happy I get to lend my voice to something like this, as well as help on the writing side when needed. :)