So I removed the old SSD (to be able to copy stuff back to a new system).
I tried to install Manjaro, but that crapped out after selecting some
settings, with a message about not being able to access /dev/loop1.
Which looked fine to me in the directory listing.

So then I downloaded the Arch Linux ISO installer and tried to follow their
installation guide. I ended up filling in some missing information from
the installation guide, started over, and got stuff installed. One issue
was that the Arch Installer generally tries to use the UEFI on this old
laptop, whereas the old Ubuntu install avoided it.

Many of my configuration settings in Ubuntu were not compatible with this new
set of software version, and I had to do a lot of editing to tweak the apps.
I also made the "mistake" of installing some PipeWire packages, which
interfered with my audio set, and which was impossible to remove. Had to
disable PipeWire using systemctl.

Rxvt-unicode doesn't work like before unless I add an -fn option to provide a
base font. So I'm back to xfce4-terminal for now.

There were a few other minor annoying issues to work through.

The last hurdle is the display manager. SDDM did not work, and seems to be in a
transition to be used as part of KDE; I could never get it to see my
xsession.desktop file. I could get LightDM and Lxdm to see it, but
both would just exit back to the login screen. Still not sure why.

So I just log in to a virtual console and run startx. I copied the .xsession
file to .xinitrc for that..

After that the system runs pretty much as before. Since I keep the machine
running all the time, I'll take my time diagnosing this issue.

It's been a long time since I've had to spend so much time provision a new
Linux system... It worked great on this Lenovo laptop.

--
I'm reporting for duty as a modern person. I want to do the Latin Hustle now!