IIRC this was already addressed and should be automatic.There was an issue specifically mentioning GDPR and the devs implemented a way to automatically delete the data of an account within the given time.
It's not a GDPR request in itself, but AFAIK a normal delete account request should be compliant... INAL
I don't think there are services like that, since usually this means deploying and destructing an instance, which takes a few minutes (if you just turn off the instance you still get billed).Probably the best option would be to have a snapshot, which costs way less than the actual instance, and create from it each day or so yo run on the images since it was last destroyed.
This is kind of what I do with my media collection, I process it on my main machine with a GPU, and then just serve it from a low-power one with Jellyfin.