EFI and cloud-init images are produced successfully; one caveat is that the networking doesn't get set quite right, so that might make it less than ideal to use.
Error message something like stages.py[ERROR]: Unable to render networking. Network config is likely broken: No available network renderers found. Searched through list: ['eni', 'sysconfig', 'netplan'], but it specifies more options in the list. It takes a while to get to login because it tries to get a connection and times out a bunch.
However image does get to login and has cloud services running. I changed kernel timings to a more server configuration (pre-emptive desktop and 250 Hz (?) timings) so the command line might seem unresponsive. I may change this back, as it's a bit uncomfortable to use. (See configs/cloud.config if you want to edit this value yourself)