mainrouter

I have two RT-AX92U routers. They are almost perfect for what I need. Both of them are in the basement and it mostly covers the main floor as well. They are wired backhaul. However, there are a few spots that are a bit flaky for signal strength on the main floor so I purchased a used...

I have three asus routers which I will use to implement Asus AI mesh.. One RT-AC86U and a pair of Asus ZenWifi XT8 AX6. I will have ethernet backbone and my question is which one I should use as main aka connection to my ISP. It seems that the XT8 have a better throuput than ac86u...