Hi, i just recently start using pihole on my RPI 4B. Unfortunately after installing and reinstalling, i cannot get internet to work on client device.
i had almost the same thing that happens to this post here. (i also uses huawei router as well)
but after following that post and using both DNS and DHCP option. internet still does not work on the clients.
interestingly when using DHCP option, my PC can use internet and got some ads blocked. but it's intermitent. (connected to the router using ethernet cable. the rpi 4 is also using ethernet)
Some of the interesting things that happens on the debug logs
[i] Distro: Raspbian
[i] Version: 10
[✗] dig return code: 9
[✗] dig response: ;; connection timed out; no servers could be reached
[✗] Error: dig command failed - Unable to check OS
(this also happens during installation. i have to use the skip os flag)
[✓] d.turn.com.akadns.net is 0.0.0.0 on lo (127.0.0.1)
[✓] d.turn.com.akadns.net is 0.0.0.0 on eth0 (192.168.18.11)
[✓] No IPv4 address available on wlan0
[✗] Failed to resolve doubleclick.com via a remote, public DNS server (8.8.8.8)
[✓] www.comarch.top is :: on lo (::1)
[✓] www.comarch.top is :: on eth0 (fe80::79d1:d748:b84:c213)
[✓] No IPv6 address available on wlan0
[✗] Failed to resolve doubleclick.com via a remote, public DNS server (2001:4860:4860::8888)
My specs
- Raspi 4 with raspbian 10
Clients - Windows 10 pc
- iPhone Xr, 11
Router : Huawei EG8245H5
Expected Behaviour:
All client should connect to internet normally. with ads blocked
Actual Behaviour:
All clients cannot access the internet 
Debug Token:
https://tricorder.pi-hole.net/kfyz6W6u/
Thanks in advance!