I think the most likely cause on your end is an interfering app or a Windows setting that you've manually set on both devices. I don't see why an Antivirus would interfere with the rendering in that way.
Mmh, well, I tend to not use any overlay apps so not many names come to mind, but Windows has a built in one with Xbox Game Bar, if your GPU is Nvidia you might have Nvidia's overlay active etc.
Good thing that it works on your brother's computer. Thank you for reporting the blackscreen issue. I think I know why it happens, I just don't understand why it would happen.. If it is what I suspect that it is, I could solve that particular issue. Are all computers Windows 10 and fully updated?