Regarding discovery specifically, this sounds ridiculous but genuinely Youtube is pretty decent for it. You just need to punch in some more obscure stuff you already like (preferably in a clean session) and it often does pull up relatively interesting recommendations.

Soulseek is a p2p client originally a contemporary of the likes of Napster and Kazaa but it has survived and kept an active user base into the modern day. Somewhere about a decade ago whenever what.cd went down a bunch of the content got dumped onto Soulseek where it has lived ever since

I host a large library of files and whenever someone downloads something from me I go and browse their collection and look for at least one album to download and add to my collection. I have found some interesting audio this way

one more olde way if you listen to out there stuff, is to go by producers/small labels/studios names of bands you already like and quickly checking bandcamp of other projects by them. Doesn’t work with popular music, works fine-ish with indies/small bands (now studios tell you the least, but producers/labels sometimes have fairly obvious tone) *(fine-ish in that you find some gems with 5-50% chance, depending on strength of producer/label niche, which have like 1-30k views on youtube, so that you make those bands much happier than getting ai ambient thingies/or bigger labels)

Plus there is something very cute and real about small labels sites, like we sold 500 vinyls woohoo posts, bands obviously post this as well, but you have to find the damned things and often they only do social networks

Youtube Music is probably the best for algorithmic recommendations and you can very easily block ads on it.

but if you want to try a different approach entirely, nothing beats just asking around for recommendations. If you find some people with similar taste as you to trade recommendations with, it is the most satisfying and fun way to discover new music.

poiskm.net is my favorite way to nab obscure songs mainly from the Former Soviet Union, not super relevant for you but I might as well give it a shoutout here because it is a good ad-free service for discovering new music

Edit: Linux Mint also comes prepackaged with Shortwave, fun little radio app

Listenbrainz might do at least some of what you want, but I must confess I haven’t made heavy enough use of it to actually vouch for it.

Personally whenever I get a craving for new music I load up either gnoosic or music-map and poke around. I think they both use the same database though, so it just depends which interface you like better.

For actually sourcing music, soulseek still exists (unsure if I’m allowed to link that here, but it’s not hard to find) and has a mobile client on f-droid. It’s also half decent for discovery too, since you can browse folders of people who show up in searches.

https://everynoise.com/ (desktop recommended)

otherwise find a genre-specific blog or writer or dj

I’ve been sort of a bleeding-edge (ie very new) music enjoyer. Most artists release music to streaming services on Thursdays at midnight, because midnight is Friday and Friday is the start of the weekend when people get off work.

On Thursday night, I look at the link below to see a list of new albums which were released and then I search for them on youtube music. I just try out different new albums. You can also click the month button to see the most popular albums of each month.

https://www.albumoftheyear.org/upcoming/

RateYourMusic (RYM) is a popular website where you can rate and review music.

https://rateyourmusic.com/charts/

My dream service would be one that could recommend music based on a given song, and provide details about the artist and things. And even better version would have an API I could tap into so I could connect the service to music assistant. Hell I’ll make a (mostly) locally hosted version of the spotify dj if I can.

You’re pretty much describing ‘last.fm’? It tracks the music you listen to in a similar way to spotify. You can install the plugin in your media player and then the website records the names of the files you play and recommends you similar music. Some people says that it’s an invasion of privacy and there’s an alternative site called ‘librefm’.

https://en.wikipedia.org/wiki/Last.fm

Rateyourmusic and bandcamp

QOBUZ is pretty good as they have an actual magazine

Soundcloud I guess

last.fm and rateyourmusic are both good for finding new music. rym notifies you of new and upcoming releases by artists you select. neither of the services have great algorithmic recommendation, but it’s very easy to fall down discovery rabbitholes. rym in particular has tons of recommendation lists made by users, and a very fine-tuneable search/filter system.

I get my recs from internet radio mostly. I rarely run into ads except for maybe donations to keep the radio running.