I never agree with opinions like that. There's not a single game in the universe that can go on for over a decade and release interesting cosmetics without breaking out of the chains of "immersion". How many more edgy black&gray dark knight larping outfits are you going to buy? Not to mention, times change, what used to be popular and desirable is now vintage at best, usually flat out boring. And what's popular now will inevitably become boring in the future, that's just how it goes.
The above screenshots of a goofy ahh edgy knight "chad" vs a guy in a pride outfit just screams homophobia, one of your real issues with "immersion", and that's why companies tend not to take any of you seriously. If you are allergic to colour and style feel free not to use the cosmetics you so despise, crazy I know.
Personally, not only do I want more outlandish cosmetics, but I pretty much won't be buying anything else from the crown store. For me to justify spending real money on cosmetics it has to be absolutely fantastic, 11/10, animated, unique and with a pony Pegasus to boot. I wanna ride Mehrunes into town if that's ever on offer. Give me an army of those sword wielding horses in Cyrodiil, that'd look so cool. Otherwise, there's so much choice in game already, especially if you consider dyes. Same reason why I passed up on the recent discounts on a merchant and a disassembler. Why would I want a boring humanoid when I can wait for a crow, a cat or a dwemer spider?
Houseguest slots are limited, so if you are looking for an 'active pub' feel, you have to kind of 'fake' it with other items like target dummies, soul shriven, and undaunted trophies.
As for overall ideas, you might want to check out existing builds via the in game 'Home Tours', or the addon EHT Housing Hub. Housing Hub actually lets you search on keywords like 'tavern' so it could be very useful in this case.
If you use discord, you can also check around for some of the Housing Related discord servers out there like Housefolio, and housing guild related servers. You'll be able to view tons of builds, and possibly have access to a lot more builders via the discords.
If you use twitch you can also try hopping into some of the housing related eso streamers to ask in chat.