can sftp be made multi-threaded?

Hello hackers@

Can sftp be made multi-threaded? Would rsync-over-ssh accomplish the same thing?

The issue I'm having is with large backups taking ages to transfer
even with both source and destination being on gigabit fibre.

It looks like sftp is single-threaded and the bandwidth per thread is
something like 5-50 Mbps and it's nowhere near saturating the bandwidth. 
Would multi-threaded sftp (if it were possible)
or rsync-over-ssh work multi-threaded on a single huge backup file?

In my example, the ssh systems are both OpenSSH_9.3p1, OpenSSL 3.0.9 30 May 2023

ty
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