So I found a cricut maker in ewaste. It needs new rollers but appears fine. However cricut are chunts and have locked the serial number out of their eco system. (I presume the previous owner upgraded).
Anywayyyy, one very spiteful detour in software development later and I've found a hilariously stupid way to regain access to the device (and possibly a bit of a flaw with cricut cloud....).
I built using a RP2040 a USB CDC Serial mitm device that emulates the pid/vid ect..., and detects when the serial number is being asked in the serial protocol, replaces that message with the serial number plus 1.
I don't have any accessories for the device so I can't show it off, but it now moves and is paired with my account.