I think your "Circle of Experts" are incorrect, in this case.
It's been confirmed by multiple people in many different configurations.
I have the RT-Systems cable, and I can download just fine, I can't upload at all.
This is the exact behavior others see. It's not necessarily a problem with the cable, so much as some sort of weird compatibility thing. I don't have an FT-60 myself so I can't really say why, but because so many people have confirmed that a better cable solves the problem, it's hard to argue.
I have tried every way possible.
- Linux chirp-next
- Linux legacy (via flatpak)
- Windows
every one of them, will download, but not upload.
You've confirmed the exact input criteria to the problem that others have solved with a different cable.
So what is the status of this?
The status is that we don't have any additional information to offer you, other than that using a better cable works for everyone who has tried. Nobody on the CHIRP dev team (that I know of) is spending nights and weekends trying to figure out why. If you want it to just work, please use the solution in #10220 :)