I had a CLP610-ND that died and seemed unfixable so I gave up on it. Aftermarket cartridges weren't the best I found.

I might have the original disk somewhere if it's likely to be the same or similar but surprised you can't find it anywhere.

I'd leave alone probably and just make sure no ports are open to it. It's probably obscure enough now, that even if there was a hole and someone got in on another device, you'd have a bigger problem with the original device being hacked...

Regarding the cloud print, do you have a NAS or pi something you could run it on?