1.- Go to https://pi.kwarc.info/historic/systems/texlive/2019/
2.- Download texlive.iso
3.- Mount the iso file
4.- Open a terminal window
5.- Go to the mounted drive
6.- Run sudo ./install-tl -scheme=full --location "MOUNTED_DRIVE_PATH"
https://medium.com/@ptantiku/texlive-offline-installation-for-windows-38aab4e3500b
You can also install MacTeX 2019 as alternative.