Ok, I've disabled the autostart of iCUE and restarted the computer (both iCUE and Dragon Center not running), but it doesn't help.
I've tried it with Launchbox 10 and the new 10.1, same result. Installing version 9.10 again and everything works fine.
It's a quite fresh windows 10 install by the way, installed it one month ago (clean install, not upgrade) with all latest updates. And I don't have much software installed. Beneath the mentioned tools I've just installed some games and game launchers (steam etc.), browsers and the normal stuff. And Kaspersky Internet Security.
Board is the X570A-Pro, as mentioned. So it's a Ryzen 3000 system.
EDIT:
Wow, I found the problem. Disabled Kaspersky Internet Security and Launchbox 10 works! So the new version is incompatible with Kaspersky!
As soon as I start Kaspersky again, Launchbox 10 fails to start.