AX88U + AC68U Mesh disappointing Internet speeds

[Sptz]

I created a thread a week ago discussing setting this as a Mesh system but this pertains to a different issue.

I've got AX88U as the main router and AC68U as a node using ethernet backhaul both using the latest stock firmware. I've got Gig Fibre by Virgin Media, speedtests inside AX88U are between 850-950 Mbps.

The issue now is with Wifi. So, I've got 160mhz disabled due to AC68U not being able match it up.
If I understand correctly, being next to either router should yield roughly the same speeds right?
But binding my testing device (laptop) to the AC68U connected to 5Ghz of course, standing next to it yields between 400-500Mbps, binding the laptop to the AX88U yields between 450-800Mbps...

This feels highly inconsistent and, I'd expect the AX88U to be at the very least not as inconsistent and test the full speed. The AC68U I'd expect to be less consistent but at least give me close to the full speed. But far from it. I'm literally standing next each while testing. Is there anything I can do to improve this?

Thanks!

 

[bbunge]

AX88U has 4x4 radios for both bands
AC68U has 3x3 radios for both bands

Should tell you that the AC68U will be slower..... but it is likely the client fault, too...

 

[Sptz]

AX88U has 4x4 radios for both bands
AC68U has 3x3 radios for both bands

Should tell you that the AC68U will be slower..... but it is likely the client fault, too...

I was expecting that obviously. But that much slower? Can't transmit more than 400-500Mbps?

The client is a laptop with ax210 I installed myself, I'm standing next to each router when testing.

Also isn't the AC68U 2x2?