Had to call the police because some kids were vandalizing a subway station. While that was going on there was a dude on a bench quietly doing what I hope was stroking his pet banana in his pants.
Yay society.
You can sync easily to another device on the same network via ssh for example. You can also call a script automatically after the backup has been created and do your custom stuff in there.
I'm really liking borgmatic myself as a wrapper for Borg.
EDIT: I don't have experience doing full OS backups. I only make backups of specific directories.
They're both good at what they do.
Personally I switched from pihole to adguard, only because adguard let's you use wildcard domains.
This lets me point all of *.mydomain.com to one IP address.
You have full control over what you block and whitelist. So if anything goes wrong, you can just troubleshoot it and whitelist if needed.
If all fails, you can always (temporarily) turn off all blocking in pihole.
My solution for a power efficient setup was to split it up: all the services I use but don't need all the time, like jellyfin for example, I host on my nas. I only turn that on when I need it.
The stuff that's running all the time, like home assistant, addblocker, etc, I run on a raspberry pi.
Might not work for everyone, but I'm happy with it.
I do exactly the same. I do not have a lot of data I feel a need to backup. I have a nightly job that zips and then encrypts my data, then rclones it to off site storage.
I had similar requirements. I switched to Baikal, which has been happily running in a docker container ever since.