Putting Hack to sleep, once and for all

Hi all,

I'm seeking advice in troubleshooting sleep in macOS on an OpenCore Big Sur Hack. It has H370M DS3H board, i3-8100 CPU and R9 380 GPU. System runs well and very stable, with all the functions working. It goes to sleep and wakes up when bothered with a keypress.

But, it does not sleep well. It constantly wakes up. Screen stays off though; I guess it's what's called darkwake in macOS.

It wouldn't be an issue at all in a fanless build. However, Gigabyte boards usually spin up fans to the fullest when booting up, before settling them down to the desired speed. And this loud noise happens every time when macOS decides to do whatever it's doing while sleeping. So basically every minute or so.

I've turned off Power Nap. I've disabled Wake on LAN in both macOS and UEFI, tried experimenting with sudo pmset commands, but it still constantly wakes up. In UEFI, I have set ASPM to on, and RC6 (Render Standby) to on.

What should I do to put this computer to sleep for good? Any advice would be appreciated, thanks.