Works! (mostly) woo hoo!

notes:

• tried “regular” shipping, and took over a month; was over the December crush, but even so was a bit surprised on how long regular post took.
• at first did not seem to work, hitting the Fn-F3 key did not do anything. Found I had to go into the settings >> Display Configuration >> select the device from the drop down DP-1, and then click >> Enabled.
• Not working with the maximum resolution of the monitor 😦 of 2560×1440 yet, says “outputs could not be saved due to error.” will update if can get this changed.
• monitor does not have any speakers, so have not tried any sound.
• update on resolution: 2560×1440 does work as a primary monitor; when “extend desktop” mode enabled, gives error. So: have two 1920×1080 screens at once, or a single larger screen. Q: what is the maximum resolution of two screens?

otherwise, have just tried the regular usb ports for my mouse

for reference, software installed:

$ cat /etc/lsb-release  
DISTRIB_ID=Manjaro-ARM 
DISTRIB_RELEASE=20.12 
DISTRIB_CODENAME= 
DISTRIB_DESCRIPTION="Manjaro ARM Linux"