Deleting files

Everyone cares about backups. But creating backups of backups of backups, or old archaic files, or temporary downloads, or massive files that are available forever on the Internet such as free software tarballs, iso files etc. is foolish. This is all to say that you need to delete files before you backup!

Get your Ducks in a row

Refer to One-liners for the 'ducks' command. Or, see the top answer at this StackExchange https://unix.stackexchange.com/questions/381391/find-biggest-files-and-delete-automatically

When Pigs Fly

GZip and Tar are the venerable workhorses for compressing files and creating archives in Linux. wp:Mark Adler created Parallel Implementation of GZip (PIGZ) that leverages multiple cores and processors. For more on pigz, and it's counterpart unpigz, see https://www.tecmint.com/compress-files-faster-in-linux/ or sudo apt install pigz and RTFM.