Thanks for the helpful responses. Just an update:

1. installing seatd did not fix the issue. :-(
2. using Ctrl-Alt-F1 worked. I could log in, became root, and search dmesg, /var/log/Xorg.0.log, and /var/log/messages. No joy, unless something got past me.
3. I tried logging in from the xfce login screen and then immediately went to the virtual console and read the logs. Again, no message that I understood.
4. Plenty of disk space. Thanks for the reminder. :-)

Next step: an important piece of info about my system I forgot to mention: I'm running Daedalus on an uptodate VMware VM, running on a Windows 11 host. I ran Chimaera in this setup without any OS issues for several years. I'm wondering if there's a problem with the xinit file and configuration. I'm going to copy and paste the Chimera Xorg config file, diff against the Daedalus config. If all else fails, I'll try logging in using the Chimaera configuration.

So far, that's all that I can think of doing. I've been doing a lot of RTFMs. ;-)

I'll report back on results.