I think this is the issue - if the community itself isn’t tagged, blocking NSFW on your account doesn’t filter the posts (although they should be blurry if the posts themselves are tagged).
Fortunately, most of the untagged communities (inc. celebs) are modded by a user called Madness, so blocking him cleared up my feed.
I bought a cheap ‘mp3 player’ from eBay when I was trying to use my phone less, but it was rubbish: no library function (just the files, listed in the order they were copied), m4a support was limited to low-complexity), Bluetooth dropped if I moved my head.
I was surprised, because there’s definitely system-on-a-chip + open-source software combinations that would make a good, cheap player. The kind of places that make them though, will always prefer to use even-cheaper components than what the final retail price would suggest.
So, because everyone uses their phone for music listening now, it’s hard to get a dumb player. They’re either rubbish, like I bought, or they’re completely at the other end of the scale (as in more expensive than a phone)