It's not that bad, and if you ask nicely you'll get some help
It really is one of the outstanding features of SME, and it really should have a bigger name for itself - it would be nice to do a panel for it. The time to rise it is measured in a few minutes.
Particularly as you don't have much data you can easily test it. Just disconnect the new backup affa box before you do a 'rise' so you don't end up with two identical machines on the network
So, the wiki page looks bad but it isn't really, though it is well worth gently reading through a few times just to get your bearings.
Essentially:
yum install smeserver-affa --enablerepo=smecontribs
mkdir /var/affa
Reboot
Add in your contribs at some point.
touch /etc/affa/backup-smeserver.conf
Add your remote server details - just swap the IP address to match
Add in extra dirs you want included eg dehydrated/letsencrypt
Make sure your remote server to back up has ssh enabled and you can login with a password to send the ssh key (test first)
Test run your backup - the fisrt will take a while. Thereafter it will be very quick as it only copies the changed files.
That's about it - tweak away.....
NB. Make sure you have enough disk space for all the 'Keeps'
You can go back and pull individual files from each backup if needed which is handy when they delete something they later wanted......
Enjoy.