Ok, So I have some more info to add to this, and not sure if it helps any. I stumbled on this today with the 2202 A point and DNS Relay disabled and connected as a 2ndary router behind another router. 
DNS relay disabled seems to work correctly behind two routers that uses a IP address setting of 192.168.0.1 on the main host router, and 192.168.77.1 on the 2nd router and the A Point router is set to 192.168.1.1 being connected behind the 2nd router.
DNS relay disabled fails to work behind one router that uses a IP address setting of 192.168.0.1 on the main host router and the 2202 A Point is set to 192.168.1.1.
I know this isn't ideal or normal configurations. 
For Item #1 DNS Relay issue:
With DNS Relay Disabled and with or with out manual DNS Addresses filled in under Internet/Advanced Settings:
Ethernet adapter Ethernet:
   Connection-specific DNS Suffix  . : ISIS
   Description . . . . . . . . . . . : Intel(R) Ethernet Connection (2) I219-V
   Physical Address. . . . . . . . . : 
   DHCP Enabled. . . . . . . . . . . : Yes
   Autoconfiguration Enabled . . . . : Yes
   Link-local IPv6 Address . . . . . : fe80::2d7e:2bb:5567:1566%11(Preferred)
   IPv4 Address. . . . . . . . . . . : 192.168.1.100(Preferred)
   Subnet Mask . . . . . . . . . . . : 255.255.255.0
   Lease Obtained. . . . . . . . . . : Tuesday, February 25, 2020 4:55:46 PM
   Lease Expires . . . . . . . . . . : Tuesday, March 3, 2020 4:55:46 PM
   Default Gateway . . . . . . . . . : 192.168.1.1
   DHCP Server . . . . . . . . . . . : 192.168.1.1
   DHCPv6 IAID . . . . . . . . . . . : 
   DHCPv6 Client DUID. . . . . . . . : 
   DNS Servers . . . . . . . . . . . : fec0:0:0:ffff::1%1
                                       fec0:0:0:ffff::2%1
                                       fec0:0:0:ffff::3%1
   NetBIOS over Tcpip. . . . . . . . : Enabled
   
I get no internet connections on 3 different PCs. I see no IPV4 DNS Server entry for IPconfig. IPv4 DNS Server entry under windows Adapter/Status for the adapter is empty. 
  
With DNS Relay enabled:
Ethernet adapter Ethernet:
   Connection-specific DNS Suffix  . : ISIS
   Description . . . . . . . . . . . : Intel(R) Ethernet Connection (2) I219-V
   Physical Address. . . . . . . . . : 
   DHCP Enabled. . . . . . . . . . . : Yes
   Autoconfiguration Enabled . . . . : Yes
   Link-local IPv6 Address . . . . . : fe80::2d7e:2bb:5567:1566%11(Preferred)
   IPv4 Address. . . . . . . . . . . : 192.168.1.100(Preferred)
   Subnet Mask . . . . . . . . . . . : 255.255.255.0
   Lease Obtained. . . . . . . . . . : Tuesday, February 25, 2020 5:02:56 PM
   Lease Expires . . . . . . . . . . : Tuesday, March 3, 2020 5:05:49 PM
   Default Gateway . . . . . . . . . : 192.168.1.1
   DHCP Server . . . . . . . . . . . : 192.168.1.1
   DHCPv6 IAID . . . . . . . . . . . : 
   DHCPv6 Client DUID. . . . . . . . : 
   DNS Servers . . . . . . . . . . . : 192.168.1.1
   NetBIOS over Tcpip. . . . . . . . : Enabled
I get internet connections on all 3 test PCs. I see a IPV4 DNS Server entry for IPconfig. IPv4 DNS Server entry under Adapter/Windows/Status for the adapter is present and is 192.168.1.1.