Check nostr:nprofile1qqsrs20qpc4hlq0ef7s3q0k7swlp79q8ys5eex3hxtmg40fccvr4yhspz4mhxue69uhhyetvv9ujumt0wd68ytnsw43qz9thwden5te0v35hgar09ec82c30wfjkccte28rd4w

I think their Bitcoin wallet allows you to backup your seed phrase

But it's on chain, no lightning