now that i am thinking about it, might want to use rclone+restic.
but again, imho, much like crypt+chunker, an overly complicated contraption for critical backups files.
as for your feature request.
chunker: add support for multi-thread uploads #5041
https://forum.rclone.org/t/rclone-copy-entire-drive/25155
https://forum.rclone.org/t/rclone-compression-zip-rar-and-data-transfer/30942/6
ok, i use veeam backup and replication.
the good news is that veeam encrypts its own .vib|.vbk files, so no need for crypt remote.
and another workaround, which i do, is have a veeam backup repository in the cloud.
i rent the cheapest vm from hetzner, run a veeam linux backup repository, which is connected to a hetzner storagebox. so, no issues with large file sizes and file verification for file transfers.
i know this is a bit off topic, but i could explain in detail...
check the rclone docs and many posts in the forum. rclone crypt remotes cannot verify file transfers using hashes.
so not trustworthy for backups.
onedrive is well known for being very slow. wasabi has no problem saturating 1Gbps fiber connection. for uploads and more importantly, downloads.