I copied the complete basedir for snac, packed it before as .tgz archive. worked pretty nice :) Some days ago i remember a post in my timeline from @grunfink@comam.es where he wrote, that he also just back up the basedir from snac during runtime.
On the old system in the datacenter, I did exactly this too, with borgbackup.
For the migration i shut the instance down, packed and copied - but this was just to be extra sure, everything is onboard.
I would think, just setup a nice daily tar or rsync job, and you should be good :)