This has been so incredible for me. Both apps available on fdroid.

In less than 5 minutes I can use reverb to record a song on YouTube I'd love to learn, import it into rubber ring, isolate the whole song, save that as a loop, isolate each a/b part, save those loops, isolate even the halves of parts to put them on loop. Rename the wav file, and get to practicing. It let's you slow down the playback up to .5 speed, which is usually where I start. It gets a little garbled, but its way better than trying to pick up and follow along at speed.

Game changer, absolutely. I wish I could share it better if its not well known. My teacher wants me to keep learning by ear, so he has me record him and do the same, but being able to get fun tunes out in the wild and quickly turn them into practice aides is awesome.

And sorry if I'm late to a well known thing.