This is causing your observation:
By way of your custom configuration, you are tying your Pi-hole to interface wlan0 exclusively, conflicting with Pi-hole's Permit all origins injecting except-interface=nonexistent.
If you remove interface=wlan0 and switch Pi-hole to its default Allow only local requests, your DNS service would be back online, covering all your host machine's network interfaces.
Your DHCP settings may yet need extra tweaking.
What's your intention here?
Serving DHCP only to clients connecting to an access point that you wish to run next to Pi-hole on the same machine?
Then you'd need some extra lines to remove DHCP services from your other interfaces, e.g.
no-dhcp-interface=tailscale0
Add one line to your /etc/dnsmasq.d/hostapd.conf for each interface that you do not want to offer DHCP services.
Check for potential syntax errors:
pihole-FTL dnsmasq-test
If OK, run pihole restartdns to take those settings into effect.