No sound/audio at all

I already tried all the troubleshooting presented in this forum and others:
Reduce to 16bit 48khz, Dolby Atmos, reduce to stereo, use a headset/box with 3.5mm plug, update video and audio drivers, reboot the PC, blablabla
No fix.

Now, wth do I do?
I REALLY don’t want to ask for a refund.