Installed linux-headers-4.15.0-23-generic, now dkms runs properly.
Re-tested w/ 4.15.0-23-generic: gdm3 STILL does not come up, just bounces between black screen and the systemd progress messages.
So, going back to 4.15.0-23-generic does NOT solve the original issue.
I will continue w/ haveged and lightdm workaround, but the bug should remain open.
Installed linux-headers- 4.15.0- 23-generic, now dkms runs properly.
Re-tested w/ 4.15.0-23-generic: gdm3 STILL does not come up, just bounces between black screen and the systemd progress messages.
So, going back to 4.15.0-23-generic does NOT solve the original issue.
I will continue w/ haveged and lightdm workaround, but the bug should remain open.