I haven’t looked very hard so there could be backup services I’m missing. So far I’ve found restic/autorestic and duplicati, but I’m not sure what their differences in purposes are or pros/cons between them.

Also I’ve heard Unraid has a flexible storage solution which would be nice as I would like to just upgrade as I go instead of planning substantial disk upgrades, but are there also solutions for that on custom built systems instead of SHR?