TUG has a great page about making a vanilla install of TeX Live to your Debian-based installation. *buntu 18.04 is stuck on Tex Live 2017. I unfortunately like to follow developments in CTAN as packages improve and new shiny things get added. Integrating that with the packaged version in the archive is a pain. There is also no known PPA or snap.
Contained herein is my slightly modified version of their suggested equivs-build control file for a metapackage to ensure apt knows that some sort of LaTeX installation is there.