First things first: don't get me wrong, I do understand your point.
The thing is: you have a system administration problem, whether you want or not (that is a big part of what you're actually paying for when you buy Dropbox or when you let Google feed on your data).
Now, as an hobbyist, when you start depending on services you set up and manage yourself, it would be a good idea to take some time to learn additional tools to enjoy your hobbies more.
Think about this as in "leveling up" your hobby.
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Now on a lighter tone, there are simpler ways to have a backup strategy, as long as you are okay with lower guarantees.
You might not use zfs, and use simple LVM snapshots. You might want to use no snapshotting at all and just do a nightly backup via a cronjob: at 3AM you just switch everything down (docker-compose down if you're using it), do a rsync to another host, start it back up. It's way simpler but you'd only get a yesterday's copy in case of problem.
But then again, that would safeguard you when doing upgrades: disable backup, perform upgrade, test everything, re-enable backup, resume operations. Worst case scenario you rsync back the yesterday's data and you resume normal operation.