Mixed AX/AC AiMesh Nodes

[JGrana]

I presently have an AX88U and an AX58U in an AiMesh configuration. It's working well for the most part.
I have an area in the back of my house where the signals are weak.
My son has offered a good old AC68U to me.
Will adding an AC router to the AiMesh reduce the overall performance?
I there any way to tell if the AX88U and AX58U are even using AX mode to backhaul the 5Ghz?

 

[archiel]

I presently have an AX88U and an AX58U in an AiMesh configuration. It's working well for the most part.
I have an area in the back of my house where the signals are weak.
My son has offered a good old AC68U to me.
Will adding an AC router to the AiMesh reduce the overall performance?
I there any way to tell if the AX88U and AX58U are even using AX mode to backhaul the 5Ghz?

I have the same setup and in Wireless Log I can see Device connections for the Router's 2.4 and 5.0 GHz MACs with name <unknown>as AX in use, 2(ax) for 2.4 and 4(ax) for 5.0. I have assumed that this is the backhaul link, but happy to be corrected.