I have a working setup... but I was hoping I could add a second thunderbolt hub to my system and unfortunately: that one addition makes my UFX+ stop working... but there is a workaround.

Setup:

Win10Pro
AMD 3900x
Asus B550-F Gaming Motherboard
Asus ThunderboltEX 3-TR Expansion
Apple TB2/3 adapter
Targus DOCK210USZ TB2 docking station
And of course the RME UFX+

The Thunderbolt expansion card has two ports, so I was figuring I could add a Caldigit Element TB4 dock there to plug in a few more things.

If I boot up the machine with the Caldigit TB4 dock plugged in in addition to the existing TB2 docking station and the UFX+, no go. Windows doesn't see any sound devices, and the RME drivers act like the UFX+ isn't present.  (though all devices do show up in Thunderbolt Control Center utility).

However!  If I boot up and enter Windows without the Caldigit plugged in... everything works fine. ALSO, I can plug in the Caldigit later on, and it and other devices plugged in there work normally.

So yeah... just an interesting thing I wanted to point out.  I don't know where exactly to lay the blame (Thunderbolt 4 itself, the Caldigit specifically, or maybe this wacky AMD/Thunderbolt thing I'm running) but I figure someone could either learn from it, or point out the underlying reasons why I'm seeing what I'm seeing.

Cheers.