Question about ASUS RT-AX88U Gaming

Probably not - it's primarily a router with WLAN. I use it as a WLAN range extender and am satisfied.

Yes, it does. The user interface of this device alone is incredibly fast. The connections are established more quickly than with my fritzbox, for example, and ASUS offers many great options in the GUI backend.
But you don't need an AX router for that. It's better to get a cheaper AC router from ASUS.