For my server I use duplicity, with a daily incremental backup and sending the encrypted diffs away. I researched a few more options some time ago but nothing really fit my use case, but I'm also not super happy with duplicity. Thanks for suggesting borgbackup.
For my personal data I have a NextCloud on a RPi4 at my parents' place, which also syncs between my laptop that I've left there. For an offline and off-site storage, I use the good old strategy where I bring over an external hard drive, rsync it, and bring it back.