How do I downgrade IME

I have Asrock Z690 Extreme WIFI 6E and since some update long ago I started having crackling, popping, I tested 8 soundcards, I know for sure it's not PSU, MEMORY, or CPU because I replaced PSU and tested another memory sticks none of them shows a symptoms of BSOD,Crashing,freezing or other weird hardware issues, games works perfectly fine.

Another test I did is using SXFI Titanium sound card on old i5-4750 gigabyte motherboard and there was not a single crackling or stuttering, on the asrock it would crackle none stop even when it won't for 1-2 sec then it would start again. I tried Optical/3.5 directly, but on ASrock it just won't work.

Also some weird issues with DPC and NDIS.sys that I never had before it would just hammer the DPC reaching over 4930.4 and always spike. a friend with gigabyte z790 and 13700K has no issues with the same network card and internet speed.

If it's unfixable I'll just buy MSI and AMD and never hear about Asrock ever again, they don't even give me support RMA or replacement or anything. worse warranty for the weirdest annoying issue. I can't enjoy music or sound anymore, also it's not just crackling and popping and sound quality degradation, like the sound would sound worse and worse randomly. I can't even explain this because I never encounter this ever in my life and it happened after some firmware update of the motherboard. nothing else was changed since.

Downgrading the bios is not enough, I updated to 18.05x and I tried almost all firmware til 14 and 13. that's including 15,16,17