it's a netgear, it doesn't have quotas.
as i mentioned i run the same command in a vm running kali and the same file has been copied without errors, same if i copy the file via SMB with windows
sincerely i don't know what's the file system it's using, it could be something Netgear propietary since i used x-raid.
i didn't try rclone on win, now i'm trying another file on both the vm and the raspi with -vv enabled, will paste log in 15 mins.
Looks like the NAS is telling you something different from Linux vs Windows.
2021/11/19 10:03:05 DEBUG : preAllocate: got error on fallocate, trying combination 1/2: operation not supported
That means it's a file system doesn't support preallocate which is a bit odd.
Perhaps you are hitting a 2GB file limit from Linux to the NAS.
Can you try to just copy a local file perhaps and see if less than 2GB works as this looks to be more something NAS/SMB related than anything with rclone directly.
anyway you are right: i tried to copy the 3 GB file from Google Drive to local ssd and then to the nfs share with the same error.
I assume this is something related to raspberry os because, again, kali works fine.
will investigate more tomorrow, thanks for your support!