I don't need wifi6; just wifi5/ + able to manage 100mbit via wireguard... and running openwrt and be small as that device 10x8x4cm .. and ideally ~200gram
Work on ipq60xx hasn't even started yet (it depends on ipq807x to get working first, but will require considerable efforts on top of that). Chances for ipq600x support are unlikely due to hardware constraints, at least ipq601x seems to be the baseline for eventual support (expect years, not months).
Right, yes it does have Openwrt, but a QSDK build of it, which has recently moved to kernel 5.4.
However just like the AX1800 not everything is compiled for it which is why I was self compiling myself untill my new server nuked my ssd's due to a bad SATA controller.
During the self compile journey I have noticed there are issues where certain packages will completely break image creation with the kernel partition jumping from 4mb to 41mb when compiling with shared kmods enabled for example.
So short answer is it will be a while before it's able to run openwrt natively.
Although it boots into openwrt the kernel is based on QSDK, native build of openwrt would be like the normal builds are like where you can download the images directly from openwrt.