Bingo. It did work indeed. I had to run sudo apt update --fix-missing some four or five times due to codeberg and then that dist-upgrade for the remaining, then do the unl0kr switch to get LUKS pw working, but I now have a “Frankenstein” LUKS Crimson with backported almost up-to-date system - Gnome 48, kernel linux 6.6.0-1-librem5, phosh 0.46… (so, quite new, a few months old [it’s what’s in the backports] - and I’m left to wonder if there are any patches there, for power savings or any other L5 specific peculiarity)
[Edit to add: I noticed that the “FrankenLUKSCrim” did not respond to my Sim8202g scripts but did find the modem after the manual procedure (three modprobes for drivers and echo+tee). It’s now also 5G capable.]