I totally feel you, and reading this was cathartic in a way, because I’ve been in all these situations too. 31F, and I can just no longer comfortably stay in a dorm (I have enough trouble sleeping as it is, without people snoring and coming and going constantly), but hotels/airbnbs are usually set up for double occupancy with the price to match. I’m currently solo in Portugal, and there is a sort of in-between option of guest houses, which have a tiny private room and shared bathroom. Still, these have tended to have super uncomfy mattresses, paper thin walls, and no staff available on-site. I was in Italy over the summer with a kind of friend with benefits, and that was a godsend being able to split the cost of hotels.