got some news. I don't think, that it might change something, but who knows.
I added in grub the option "insmod progress" (which I found by googling somewhere). It should show, if kernel and initrd do load or not and now I can see, that the vmlinuz and initrd are loading to 100% and after that it hangs. So it looks like the kernel loads but then stucks.
As said before, I don't think that this might change something in regards to further tests with my actual mobo, but I didn't want to left that out ...
@rufus
thanks for taking the time. I already asked over at the asus-linux discord about the issue but got no reactions up until now.
did already, unfortunately not working
all installers (except nobara) do fail when trying to get the bootloader installed, since efibootmgr seems to be in need of the acpi options and I don't get it running with acpi option on.
that's exactly what I'm trying to do, first and most important (from my understanding) would be to get the OS booted from the USB with acpi on. I am going through google/DDG/qwant/whatever-search-engine to look it up and tried everything I was able to find in relation to my Hardware, but wasn't able to tackle the issue up until now, that's why I'm asking for help all over the reddits/lemmys/kbins/discords...
I can get Nobara - and only Nobara - installed so I can boot without USB, but there as well only with acpi off.
I tried with Fedora, Nobara, ubuntu LTS, pop!_os, GarudaOS, silverblue, Mint, with everyone having the issue not being able to boot without acpi=off and getting to a black screen and USBs (seem) powered off right after choosing the OS in grub.
appreciate your time replying, thank you.