A kind of backup can be done by scanning "ECU info" as shown in Lighting MadnessHi Guys.
After reading this I've just ordered one from Amazon, should get it tomorrow.
When you use it for the 1st time, is it possible to back up existing settings, just in case?
The ECU info contains line "Coding: ...." for each module in hex-format which is the full data needed to revert back to original state. Some effort is needed but is definitely doable.
However, some of the modifications are done via so called adaptations. I do not know if there is a similar way to back up those in Carista. The VCDS tool can back up those so certainly it can be done.
And of course you could ask @Don Carista to implement more user friendly back up functionality in their future release.