i’ve been with Apple since day one and have a lot of legitimate music, but also a lot of music that i ‘bought’ through apple music subscription.

I now have a Samsung S76 Edge and i’ve stopped Apple music and downloaded some stuff on spotify on both phones I use.

Is there any way I can download on one and make it automatically download on the other so they’re both available offline, without having to do it for each device?

any other tips appreciated.

I think all you need to do is make it available off line.

I use the “my library” function. All tracks,albums,playlists go there and will be available regardless of what device I use to login

Your playlists will be available on whichever device you pick up, and you can even remotely activate them (use your phone to dictate the music your PC plays, for example).

As for playing music offline, you’ll need to identify it on each device individually; select the song/album/playlist/artist and check the ‘make available offline’ button.

^^ What Duffer said. Additionally, to have your designated ‘available offline’ music available actually offline you will need to download it to the memory of each device, which can take a little while, depending on the length of your playlists.