I finally got iCUE v4 working (not crashing upon startup) after upgrading from v3. It required me to use the Windows Device Manager to manually uninstall ALL Corsair devices and their drivers on the computer (don't restart computer after uninstalling) before running the iCUE v4 installer.
So far no problems detecting and running:
Corsair Vengeance RGB Pro ram
Corsair H150i Elite Capellix AIO cooling
Corsair Dark Core Pro SE mouse
Corsair Dark Core Pro SE Wireless Receiver
Corsair K100 RGB Keyboard
Corsair ST100 RGB Headphone Stand
Corsair HS70 Wireless Headphones
Corsair iCUE Nexus
iCUE v4 did NOT detect:
Corsair MM1000 Rigid Mouse Pad (although it works and charges mouse).
I have to give a shoutout to Corsair for making the H150i Elite Capellix a breeze to install even squeezed into a Corsair 220T RGB mid tower (see pic) although I couldn't install the bottom 2 radiator screws because the case holes weren't big enough. It doesn't effect the stability of the radiator or fans in the case however.
I do have an iCUE software suggestion other than having it detect the MM1000 mouse pad. I would like a lighting link indication for the battery status of both wireless mouse and wireless headphones. Essentially, I would like to visually show the battery charge status of the devices using the mouse LED's and ST100 LED's. Something along the lines:
Red : 30 %
Yellow: 50 %
Green: 70 %