Company upgraded me to Ubuntu 18.04 and now all tiling window managers are borked. Plaease... halp...

I don't know how, but upgrading from 16.04 has broken ALL tiling window managers in one of two ways: the ones I try to build from source fail because the 18.04 toolchain is already too old, and the ones I install via apt fail by sending nothing to the monitors after I've logged in at the desktop manager. It's not just blackness either, my external monitor thinks it has been unplugged and goes hunting through other inputs. If I use Ctrl+Alt+F1 I get back to GDM, which shows me as logged in but locked, although typing my password again just repeats the blackness.

This latter failure mode happens with all combinations of: Wayland, X11 crossed with awesomewm, xmonad, dwm, i3, subtle, notion, spectrwm, tritium, herbsluftwm, and stumpwm. Which is crazy to me that an OS update can identically break everything.

To make matters worse, IT requires that we run BitDefender, so everything something fails and I have to reboot it costs upwards of 5 minutes.

Please help! Concurrently I'm also trying to get IT to help, but they say it's not their problem on account of whatever version of Gnome on Wayland technically working (in other words, being a PITA to use doesn't count as being broken).

Edit: Progress! It seems that nVidia drivers were indefinitely pausing systemd (because obviously that's what they should be doing) (... and also can we pause and reflect on how little progress we've made as an OS? I feel like I've been battling this very issue with every major new version for the better part of a decade). I switched to intel graphics and I can now get into awesomewm... but now I'm facing some DPI garbage where my mouse pointer is the size of a B52 (no joke, the I-Beam cursor for entering text is three lines of text tall). Any advice for how to shrink it to a sane size, say, somewhere in the neighborhood of a capital letter?