good to know. and that explains everything.
sure, winfsp needs to be installed where rclone is executed. i just assumed that from that start.
what threw me was the generic error you got,
Fatal error: failed to mount FUSE fs: mount stopped before calling Init: mount failed
that had me thinking that winfsp was installed in the container, and the issue was a config issue, permissions issue, or something like that.
as normally, if rclone cannot find winfsp, it outputs a very specific error.
Fatal error: failed to mount FUSE fs: mount stopped before calling Init: mount failed: cgofuse: cannot find winfsp