Resolving pihole DNS issues by making it my DHCP server?

I'm using pihole as my local DNS resolver to access my services through nice local subdomains. The DNS server is advertised to devices via my router's built-in DHCP server. But the Android devices on my network are driving me mad: Although I've blocked DNS(SEC) access in the firewall and I have disabled "Private DNS" on all Android devices, they always find a sneaky way around my local DNS and contact Google's DNS servers to resolve URLs.

I've read that people got this problem solved by enabling pihole as the network-wide DHCP server. I don't see why it would, though. Can anyone here confirm with any certainty that this will also force my misbehaving Android devices through pihole's DNS?