We deferred to switching to the new installer until 22.04 and kept using the legacy net boot image for as long as possible. The switchover wasn't as bad as I was afraid it would and took only a few days to make new internal app to drive our installations. The worst part of the new installer is it requires a minimum of 2GiB of RAM to run, so all of our new VMs have to start with at least that much and be scaled down later