This is a companion discussion topic for the original entry at https://linuxconfig.org/how-to-increase-tty-console-resolution-on-ubuntu-18-04-server
Thank you thank you thank you thank you! There is soooo much information out there that is so out of date and doesn’t work at all on 18.04. It took me half a day, but I finally found your post and it did the trick!
Of note to anyone else trying to go above 1024x768 - despite my display being 16x9 and 4k, I was only able to use 4x3 resolutions up to 1920x1440, which I actually found a little hard on the eyes on a 15", so I ended up going with 1600x1200.