Borg you can reconfigure the chunkier settings to tune memory and space usage depending on what type of files you're backing up (large VMs, small text files, etc)

There's some notes in GitHub issues with some recommendations

There are also implications for backup speed so I'm not sure such a naive test tells much (and maybe the other programs tested have similar configurables?)

On another note, for encryption, I just copy the key to LastPass or make an aes 7z and upload to Dropbox/Google Drive. In big cases, the data gets synced locally to devices with the client installed