Mesh experts Xiaomi AX3600/AX1800? ethernet over wifi issue

Hi Guys, done a lot of reading on the forum and have AX3600 with latest firmware & permanent SSH and AX1800 with latest firmware & SSH too (not permanent on this one).

I have a Mesh setup where the AX3600 is the AP and two AX1800 mesh repeaters. They are both also connected with ethernet cat 7 cables.

My issue is that the basement AX1800 seems to be doing mesh via the ethernet cable, achieving speeds of 950 Mbps where as the first floor AX1800 seems to be doing mesh via wifi with speed around 300-400 Mbps.

My question is how to configure ethernet priority over wifi. I have compared both etc/config/network files and they are the same except for the different unit IP´s of course, so I have a feeling this has to be configured somewhere else, but do not know where...

did u found a solution? I have 3 ax3600 and setup a mesh with 1 of them as ap.
how did u connect them? (ports?) and did u find a solution to prio. ethernet over wireless?