Yesterday I updated my computer using apt and walked away to let it run. I ended up being away from it for a few hours. When I got back I saw that it was done, so I closed the terminal and shut the system down. When I turned it back on later, it got to the login screen but never showed the desktop. Only a black screen with a cursor. I switched to tty1 and that was working normally except apt would not update and I couldn't connect to wifi. I tried googling for solutions and ran journalctl -xe which showed both the network manager and lightdm trying to start and failing.
Here is a list of the packages apt upgraded before this issue started
fdisk:amd64 (2.31.1-0.4ubuntu3.6, 2.31.1-0.4ubuntu3.7) libpackagekit-glib2-18:amd64 (1.1.9-1ubuntu2.18.04.5, 1.1.9-1ubuntu2.18.04.6) uuid-runtime:amd64 (2.31.1-0.4ubuntu3.6, 2.31.1-0.4ubuntu3.7) libfdisk1:amd64 (2.31.1-0.4ubuntu3.6, 2.31.1-0.4ubuntu3.7) gnupg-utils:amd64 (2.2.4-1ubuntu1.2, 2.2.4-1ubuntu1.3) python-samba:amd64 (2:4.7.6+dfsg~ubuntu-0ubuntu2.18, 2:4.7.6+dfsg~ubuntu-0ubuntu2.19) linux-libc-dev:amd64 (4.15.0-117.118, 4.15.0-118.119) gpg-wks-client:amd64 (2.2.4-1ubuntu1.2, 2.2.4-1ubuntu1.3) geogebra-classic:amd64 (6.0.604.0-202009091124, 6.0.606.0-202009222237) gnupg-l10n:amd64 (2.2.4-1ubuntu1.2, 2.2.4-1ubuntu1.3) libproxy1v5:amd64 (0.4.15-1, 0.4.15-1ubuntu0.1) libproxy1v5:i386 (0.4.15-1, 0.4.15-1ubuntu0.1) finalrd:amd64 (3~ubuntu18.04.0, 6~ubuntu18.04.1) libwbclient0:amd64 (2:4.7.6+dfsg~ubuntu-0ubuntu2.18, 2:4.7.6+dfsg~ubuntu-0ubuntu2.19) libmount1:amd64 (2.31.1-0.4ubuntu3.6, 2.31.1-0.4ubuntu3.7) libmount1:i386 (2.31.1-0.4ubuntu3.6, 2.31.1-0.4ubuntu3.7) samba:amd64 (2:4.7.6+dfsg~ubuntu-0ubuntu2.18, 2:4.7.6+dfsg~ubuntu-0ubuntu2.19) libproxy1-plugin-gsettings:amd64 (0.4.15-1, 0.4.15-1ubuntu0.1) samba-dsdb-modules:amd64 (2:4.7.6+dfsg~ubuntu-0ubuntu2.18, 2:4.7.6+dfsg~ubuntu-0ubuntu2.19) python3-aptdaemon.gtk3widgets:amd64 (1.1.1+bzr982-0ubuntu19.3, 1.1.1+bzr982-0ubuntu19.4) gpg-wks-server:amd64 (2.2.4-1ubuntu1.2, 2.2.4-1ubuntu1.3) util-linux:amd64 (2.31.1-0.4ubuntu3.6, 2.31.1-0.4ubuntu3.7) gpg:amd64 (2.2.4-1ubuntu1.2, 2.2.4-1ubuntu1.3) cifs-utils:amd64 (2:6.8-1ubuntu1, 2:6.8-1ubuntu1.1) dirmngr:amd64 (2.2.4-1ubuntu1.2, 2.2.4-1ubuntu1.3) mount:amd64 (2.31.1-0.4ubuntu3.6, 2.31.1-0.4ubuntu3.7) samba-libs:amd64 (2:4.7.6+dfsg~ubuntu-0ubuntu2.18, 2:4.7.6+dfsg~ubuntu-0ubuntu2.19) libblkid1:amd64 (2.31.1-0.4ubuntu3.6, 2.31.1-0.4ubuntu3.7) libblkid1:i386 (2.31.1-0.4ubuntu3.6, 2.31.1-0.4ubuntu3.7) busybox-static:amd64 (1:1.27.2-2ubuntu3.2, 1:1.27.2-2ubuntu3.3) libproxy-tools:amd64 (0.4.15-1, 0.4.15-1ubuntu0.1) samba-common:amd64 (2:4.7.6+dfsg~ubuntu-0ubuntu2.18, 2:4.7.6+dfsg~ubuntu-0ubuntu2.19) firefox-locale-en:amd64 (80.0.1+linuxmint1+tricia, 81.0+linuxmint1+tricia) libuuid1:amd64 (2.31.1-0.4ubuntu3.6, 2.31.1-0.4ubuntu3.7) libuuid1:i386 (2.31.1-0.4ubuntu3.6, 2.31.1-0.4ubuntu3.7) mintdrivers:amd64 (1.4.1, 1.4.5) gpgv:amd64 (2.2.4-1ubuntu1.2, 2.2.4-1ubuntu1.3) libproxy1-plugin-networkmanager:amd64 (0.4.15-1, 0.4.15-1ubuntu0.1) libsmartcols1:amd64 (2.31.1-0.4ubuntu3.6, 2.31.1-0.4ubuntu3.7) rfkill:amd64 (2.31.1-0.4ubuntu3.6, 2.31.1-0.4ubuntu3.7) python-aptdaemon:amd64 (1.1.1+bzr982-0ubuntu19.3, 1.1.1+bzr982-0ubuntu19.4) libsmbclient:amd64 (2:4.7.6+dfsg~ubuntu-0ubuntu2.18, 2:4.7.6+dfsg~ubuntu-0ubuntu2.19) smbclient:amd64 (2:4.7.6+dfsg~ubuntu-0ubuntu2.18, 2:4.7.6+dfsg~ubuntu-0ubuntu2.19) samba-common-bin:amd64 (2:4.7.6+dfsg~ubuntu-0ubuntu2.18, 2:4.7.6+dfsg~ubuntu-0ubuntu2.19) aptdaemon-data:amd64 (1.1.1+bzr982-0ubuntu19.3, 1.1.1+bzr982-0ubuntu19.4) bsdutils:amd64 (1:2.31.1-0.4ubuntu3.6, 1:2.31.1-0.4ubuntu3.7) libssl1.0-dev:amd64 (1.0.2n-1ubuntu5.3, 1.0.2n-1ubuntu5.4) gnupg2:amd64 (2.2.4-1ubuntu1.2, 2.2.4-1ubuntu1.3) code:amd64 (1.49.0-1599744551, 1.49.2-1600965325) python3-aptdaemon:amd64 (1.1.1+bzr982-0ubuntu19.3, 1.1.1+bzr982-0ubuntu19.4) gir1.2-packagekitglib-1.0:amd64 (1.1.9-1ubuntu2.18.04.5, 1.1.9-1ubuntu2.18.04.6) firefox:amd64 (80.0.1+linuxmint1+tricia, 81.0+linuxmint1+tricia) aptdaemon:amd64 (1.1.1+bzr982-0ubuntu19.3, 1.1.1+bzr982-0ubuntu19.4) gnupg:amd64 (2.2.4-1ubuntu1.2, 2.2.4-1ubuntu1.3) python-aptdaemon.gtk3widgets:amd64 (1.1.1+bzr982-0ubuntu19.3, 1.1.1+bzr982-0ubuntu19.4) gpg-agent:amd64 (2.2.4-1ubuntu1.2, 2.2.4-1ubuntu1.3) gpgconf:amd64 (2.2.4-1ubuntu1.2, 2.2.4-1ubuntu1.3) libssl1.0.0:i386 (1.0.2n-1ubuntu5.3, 1.0.2n-1ubuntu5.4) libssl1.0.0:amd64 (1.0.2n-1ubuntu5.3, 1.0.2n-1ubuntu5.4) base-files:amd64 (19.0.1, 19.0.2) gpgsm:amd64 (2.2.4-1ubuntu1.2, 2.2.4-1ubuntu1.3) busybox-initramfs:amd64 (1:1.27.2-2ubuntu3.2, 1:1.27.2-2ubuntu3.3) and here is the output of journalctl -x --since='2020-09-30' (pastebin has an upload limit, so I had to trim the log down. I think I got the useful bits. A lot was pages of lightdm saying it couldn't open files.)