First, try the 2.5 Ghz WAN port for internet input and see if that is any different for you with the AX11000.
In terms of WAF and a very good router check out the ASUS ZenWiFi AX (XT8).
https://www.asus.com/us/Networking-...i-System/ZenWiFi-WiFi-Systems/ZenWiFi-AX-XT8/
You can get white or black, you can get 2, 3, or 4 units. Wireless or Ethernet back-haul, and it has three built in LAN ports. All the units are identical.
I've owned the Eero, and this router (XT8) kills it. Also, if you're accustomed to the AsusWRT interface, you'll love this. It has AI mesh 2.0. And now the Asus mobile app is fantastic, it caught up with and passed the Eero mobile app.
Another plus is you can also keep your old 5300 (which is still a very good router), find a place to hide it and add it into the Asus AI Mesh pool!!
Check it out, I hope my suggestion helps you.