GL504GM - no HDMI audio device at all and can't run nVidia control panel

[Philomorph]

I have a ROG Strix Hero II laptop, about a year old. FOr the first time I tried plugging it into my TV via HDMI, but there's no audio.

I went to change the audio to HDMI and it's not listed. The only audio device listed is the realtek speakers.

I reinstalled the nVidia drivers (clean install) but no change.

I checked the device manager and there's no device showing for nVidia audio. I checked audio devices and nothing is listed, disabled, hidden, or otherwise.

I have the latest drivers from nVidia and GeForce experience runs fine. Everything else works.

EXCEPT - nVidia control panel won't run. It's in the start menu, but I select it and nothing happens.

I googled for solutions but nothing I found works, or seems strictly relevant - they all assume you at least have the device listed somewhere, or just suggest reinstalling.

So I decided to try installing the version from the ASUS website for my specific model, which says it's Version V25.21.14.2546
2020/05/25. When I ran it, it complained "The standard NVIDIA graphics driver is not compatible with this version of Windows." and suggests installing it via GeForce experience (which is what I already have). So no joy there either.

Ideas?

[Blake@ROG]

Hello Philomorph,
Do you have another device you can connect your HDMI to cross check?
And what brand and model is your TV?
Thank you.