But, both needs to set Pi-Hole custom DNS ("Custom 1 (IPv4)") to a different value:
router IP for DD-WRT
127.0.0.1#5053 for DNS-Over-HTTPS
How can I combine the both ?
I don't understand exactly why DD-WRT router IP needs to be set as custom DNS in method 2, so I am not sure I can overwrite it with 127.0.0.1#5053 without issue.
The reason it says to use the router's IP is so you can get local hostname resolution. You can use the conditional forwarding feature in the settings page to forward local domains to the router for resolution.
I am not on development branch but on master (I don't know how stable is the dev branch).
I see a "CONDITIONAL_FORWARDING" option in "/etc/pihole/setupVars.conf"
Is equivalent to set it to "true" and adding following in file ?
CONDITIONAL_FORWARDING_IP=Router IP
CONDITIONAL_FORWARDING_DOMAIN=Domain name on router