It's nice that such programs have a free entry point, but the downside is the constant comms back to the mothership. I try to avoid them wherever possible. If your sites don't have a hosts file, dns sink, pi hole, or other scheme to block the comms (and shouldn't this be a standard these days?), then it's time to investigate other free backup tools.
At one point, Macrium Reflect has/had a free version, in their 7.0 and 8.0 releases ... you can probably still find these. The paid version can be had inexpensively during BlackFriday sales & such. If doing support, then perhaps their initial inexpensive cost can be justified, under any kind of MSP scheme ...
I use reflect extensively, paid and free versions ... add to the paid pool whenever a sale comes up. Not all of my machines or vm's need a paid feature set.
Hope this helps ...