Hetzner Cloud snapshoot can be an additional measure in case of total backup failover, but as @fbartels said, snapshoot could have inconsistent data and generate corrupted instance when recovery-restart.
Snapshotting an instance can be an extreme way to recovery data. Of course, cannot be the first and the right way to make a restore. If you use that feature to make it cheaper I think is not a good way to approach problem.
As @jdaviescoates said, you can purchase a Box from Hetzner and configure an extra backup, mounting CIFS directory. But also this procedure can have some risks in case of a total failover of Hetzner datacenter or connection. Best practice is to use a different provider or datacenter.
Question is: @mikulabc why you want to use Snapshotting feature? To be cheap?
For the most part though, the domain registrar will handle that part of forwarding a full domain to another if you use their own DNS servers, etc. I have done that for a couple of my own domains that I had registered a long time ago for 10 years, but no longer use them so wanted to just forward them to my current ones instead.
It would certainly be convenient for Cloudron admins if Cloudron did this too though. One example I can think of... I have two vanity URLs purchased by two different clients of mine where they want me hosting their email but for the website they want it going to their realtor agency website (for example) which is outside of my control, and would be convenient to set it all in the same space instead of a mix of domain registrar and Cloudron.
@girish Oh, absolutely with a custom app, I mentioned in the original post that I'm going to build my own Wordpress Stack to simply and only add this. But I saw benefit to other user's being able to script something post-update as that's literally the only thing my stack will do differently than the default Wordpress app (I'll have to integrate your updates into my stack manually each time so I still wish there was a way to run an external custom sh script post-installation).
As you can see my custom script simply uses the CLI to upgrade all databases with any new required formatting if and only if any updated Wordpress core or updated plugin require it. When you update from the Cloudron interface, it simply updates all the files and Wordpress has this really annoying tendency to not upgrade the databases post-upgrade invisibly. The script above is the only way to make sure file versions and database versions stay in sync 100% of the time every update.
This becomes nearly unavoidable if you want to support multisite in the future since the problem becomes more convoluted in that installation type so my script detects multisite installations and runs database upgrades accordingly with WP CLI commands or single site only commands if it's a single site.
I actually think the script below should be an optional "automatic upgrade plugin and themes checkbox when updating Wordpress core" option for Wordpress installations as well, here's the WP CLI code for it: