Ideally, rclone would detect if it is a duplicate name or name+content and word the error accordingly.
I don't think there is any way to do that right now, as you can see in my examples for some files rclone cannot produce an md5sum, nor the file has a size (it is -1). Therefore no way to know for rclone, as it is now.
So something like:
ERROR: Stargardt_Summary .xlsx: Duplicate folder/file name. Content might differ. Use rclone dedupe to find and fix duplicate names.
Might not be the perfect wording, but for sure catches attention and forces the rclone user to go a bit deeper and understand what is really going on.
My 2 cents.