A lower tech version would be to pick a very long recovery passphrase, cut it in two or three and give it to two or three friends. It doesn't give you N out of M, but it will be good enough for a lot of real world scenarios
I don’t know. Depending on how much time passes between now and the moment you try to recover the key I bet at least one of your friends will have misplaced or lost that piece of paper.
