Cool, are there Youtube videos of this? What would I put in?

I actually clicked because I completely feel you. It's not nothing. You're spending how much time in there and textured walls and ceilings and weird light fixtures really do have a bizarre energy I don't like either. "Funky fabric," isn't going to do it, that's a totally different vibe. I like where your head's at. It's actually pretty labor intensive to sand down walls/ceiling, but def worth checking into and seeing if the owner would be down. What is even the point of popcorn ceilings? Just laziness? Textured walls? Because painting a board flat is hard? I don't understand. I do think maybe stretch like raw hide and wooden boards with maybe barn door slats on them could cover them up? Hmmmmmmm....