Bobbox

So if this works for you and you apparently know how to change bootloader, I can not really say or conclude more in addition to what is already said. I do not use images nor Imager and also do not own the ITX, I only tried to see if this issues is maybe something RK3588 generic.

As expected. Mainline Linux support for rk35xx soc family is still under heavy development. There is a good overview what should work and what does not:https://gitlab.collabora.com/hardware-enablement/rockchip-3588/notes-for-rockchip-3588/-/blob/main/mainline-status.md