I have a Veracrypt container file that does not update modification time or size by default (though I have been forced to change the default behavior, both because of this and of Nextcloud). So I naturally want to use --checksum in the command. However after much testing it seems it is just not possible because
I have this set for the user "xyz" in the sshd_config of the destination to lock down the user logging in to a strict sftp environment.