I didn't receive an email from your message. Is that due to the forum migration, possibly?
Good news though, I rebuilt the server with Ubuntu 24.04 + WW 2.20 + Apache and here is the current state of things:
LDAP: Working fully
Canvas LTI 1.1: Working fully
Canvas LTI 1.3: Same symptoms as before, but this was only a quick test.
Shibbolith: Untested
To answer your previous questions, I was being sent to ".../ltiadvantage/login", so I believe the links were proper. I think I tried both iframe and new window, but I can't say for certain. Firefox on Linux is where most of the testing has taken place, but I have tested in Firefox (Linux), Chromium (Linux), Firefox (Windows), Chrome (Windows). All of the testing in this paragraph was done on the previous install.
Due to the beginning of the semester starting next week, we are electing to keep this in its current state until the next semester break (late December). I will likely test some of these in a sandbox to see if I can work out any of these kinks before the break.