The list of Devices is visible all the time - no need to click the cog icon.
You can see I have the RTL-SDR (USB) selected properly. I believe I've done my due diligence. I tried every SDR option in the list - none worked.
When I click the cog icon, with the RTL-SDR (USB) selected, I get a window called RTL-SDR Controller.
The Device box is empty and there is no way to select a device for that empty box. I have several years of experience using the RTL-SDR and SDR#.
I have it configured and working fine on a Windows 10 laptop.
This is a case where the software or driver is not working properly, on one particular PC.