“This time, because the changes to the underlying architecture are so significant, we are not suggesting any procedure for upgrading a Bullseye image to Bookworm; any attempt to do this will almost certainly end up with a non-booting desktop and data loss. The only way to get Bookworm is either to create an SD card using Raspberry Pi Imager, or to download and flash a Bookworm image from here with your tool of choice.”
that is the same bs rpios says with every release. most likely they just don’t want the forum with a bunch of people having ods issues.
I installed rpios on my pi400 three yrs ago then changed the Debian repos to Sid and updated. Been doing apt upgrade ever since with no problems.