Hi
The following was purchased from Amazon.co.uk, it was a choice based on the quality of Ugreen USB C leads and Connector Convertors:
Ugreen Port Adapter
It is short on USB C ports but, with the correct Converter, easily makes a USB 3 port available as USB C.
Ports:
1. USB C - Power In
2. HDMI - Large Screen Display
3. USB 3 - Converted to USB C - Crucial X8 External 2TB Drive - Time Machine
4. USB 3 - Logitech Unifying Receiver - Wireless - Logitech MX Ergo - Serves MacPro5.1 + MacBookProM1
5. Card Reader - Not tried yet
6. Card Reader - Not tried yet
Everything works as expected, subject to the odd glitches of the M1, although pretty good all round.
The large screen is used with the M1 or the 5.1 without the need for pulling or inserting connectors.
With the built in M1 Display + Large Screen displaying the 5.1 the MX Ergo can control both.
Also it is possible to
Copy from one computer and
Paste on the other.
The tricked out 5.1 is running the latest possible macOSX High Sierra 10.13.6.
Looking to UpGrade to include at least 1 extra USB C + Gigabit Ethernet connections.