Great guide! You can send lightning channel backups (SCBs) to nostr:nprofile1qqsz4uq7p44arw0mh83agv2h6ezep7e8mnau403g0p99svhp00hms7cprfmhxue69uhkummnw3ezu6rpdej8j6n4de4hjtnrdaksz8thwden5te0vakx7cnpdskhyetvv9ujucm9wd3juarjv9jx2qfzwaehxw309ahx7um5wfjkzmfdw3jhxapww4czuunpd9k8wcte9eshququcjzc3 automatically using Thunderhub for free. The SCB files are already encrypted by default.
It's not a completely self-sovereign thing to do, but maybe as a backup to the backup.