Rob,
It is really important to have packages available on the latest releases as soon as possible so that people who do have to keep the O/S upgraded, have some packages available right away. And as you already know, there are only so many partitions available to use for the operating systems so something has to give !!
AppImage is always available to run just about any where. BUT, I realize that as a programmer, the advantages of the package can be more desirable. That said, ELIVE has the 3 latest Debian packages available (as announced on the News on the
cinelerra-gg.org website) and Bullseye, version 11 package is at: