I have installed texlive on Windows 10 and took me several hours to do this. Approximately 6 Gb of packages were downloaded. Now I have a folder C:\texlive If I take a backup of this folder then my assumption is my installation is backed up. If I have for some reason to install texlive again then just copying this folder to C drive will do the needful. Or I need to do something else to do installation. Let me know how to resume things in case of using this backup directory on a new system.
You can use
tlmgr to make a backup:
tlmgr backup --all --backupdir directory
tlmgr restore --all --backupdir directory
to restore the backup.
Or you use a portable installation to switch systems: https://www.tug.org/texlive/doc/texlive-en/texlive-en.html#x1-420004.2