My wifi experience disconnection sporadically

I am new to the pi-hole environment.

This is the debug token:

I am using USG as the router, Orbi as the AP and Synology NAS as the DNS Server when the pi-hole runs on the docker in host network.

I have two issues. Even if i have configured the router setting to include DNS in LAN for synology server address, I am not able to automatically track all devices on the network. I can only access pi-hole function if I maually set on the ipone or ipad for DNS server address.

Secondly, my wifi often show a temporary non-working when internet is down for short-period.

Please help me to look at the issues.

Thank you.

I may not understand your issue correctly.
In case you expect to see Pi-hole's Query Log registering DNS requests from individual devices:
That won't work if your router only is configured to use Pi-hole as its upstream DNS server.
Though your network will still be filtered by Pi-hole, all queries will originate from your router in such a configuration.

See also Pi-hole's Post Install documentation.

Thx for the reply. I did read the link you posted. Here is my router set-up. I understand that by setting the router have only the p-hole server ip address as the DNS server and it can then be used for all the devices on the network as DNS server.

Could you also help me to check the debug information and see whether any reasons are for periodic disconnection of my wifi?