Keep in mind that you are only getting a few negative experience responses. There are likely others who are not having issues with their Asus router. Everyone's LAN/WiFi client environment and use case are different.This makes me nervous about spending a good bit on a newer model only to be a waste of time. How does ASUS expect to keep customers if their high $ routers are unreliable?
Personally for my use case and environment, replacing a RT-AC68U with a RT-AX86U Pro have been a positive experience. Getting better WiFi connections with my WiFi clients than I did with the RT-AC68U. One thing I have found in my use case is certain IoT devices and a HP printer were picky about having "WPA3-Personal" enabled on the router. Ran into problems trying to use "WPA2/WPA3-Personal" with a number of my IoT devices so had to roll back to using only "WPA2-Personal" instead.