How to setup pihole on Asus GT-AX11000?

I tried following https://www.asus.com/support/faq/1046062/, but when I set my WAN DNS to my pihole’s IP, I can’t hit anything on the internet. Settings in: WAN –> WAN DNS Setting –> Assign –> Manual Setting.

I also tried setting my LAN –> DHCP Server –> DNS and WINS Server Setting –> DNS Server 1, DNS Server 2, WINS Server. I set all of these to my pihole’s IP, but that doesn’t seem to do anything, i.e. I don’t see any queries in the pihole dashboard.
I also set “Advertise router’s IP in addition to user-specified DNS = No”, fwiw.

I jsut switched form an old netgear 6800 where the pihole worked brilliantly, so I’m skeptical that it is the problem here, but I’m not sure how to fully verify it.

Device versions and info:

Asus GT-AX11000 - Operation Mode:Wireless router Firmware Version:3.0.0.4.388_24328
Pi-hole version is v5.17.3 (Latest: v5.17.3)
  web version is v5.21 (Latest: v5.21)
  FTL version is v5.25.1 (Latest: v5.25.1)