Raindrop.io. I use the Firefox extension on desktop and the android app. Bookmarks are in the app, not actually in the browser, but it’s simple and it works. It also makes bookmarks easier to search.

Correct, I have to manually select which device to play from, but Spotify also remembers the current playlist when switching. Tidal doesn’t, device sessions are separate.

Spotify doesn’t remember the queue though, so shuffled playlists get reshuffled when switching devices. It causes repeats and it’s really annoying. Deezer has the best session management I’ve used. It remembers the whole queue.

Seamlessly switching between music players. I can have a song playing on my computer, then switch to my phone when I get in the car.

I tried Tidal earlier this year and that was one of the main complaints I had. Their version only works on specific devices that Tidal is partnered with.