I had a problem with my Bluetooth, and rather than slog through a million different possibilities, and given that it's a new installation of Zorin OS anyway, I decided to reinstall. That also gave me the chance to fix a few things I hadn't done quite right to begin with (such as setting up the L2ARC cache drive with a proper GPT layout and with the device name rather than device path as the identifier, so if the device path changes (ie: from /dev/sdb1 to, say, /dev/sdb3) when the drives plugging in change, ZFS still works properly.
Anyway, I reinstalled, got it all set back up the way I wanted, rebooted that final time and... it hung right before the desktop background image loaded!
So, I went into troubleshooting mode. I made one change, then rebooted, made another change, then rebooted, etc.
Come to find out, after I installed the Synaptics driver and rebooted to enable it as described above, that's when the problem replicated. So I rolled back using the Grub menu and I'm back up and running.
But just know that the installation has changed, apparently... for instance, Intel CPU microcode updates are rolled into the installation now, and my touchpad isn't nearly as over-sensitive as it was, even without the Synaptics driver... and whatever changed is causing my machine to hang right before the desktop loads.