Yes it is disabled.
I was able to block requests with the firewall, but what I want to do is actually forward requests to port 53 to my local DNS server (Pihole) using static routes - or at least back to my router.
Pretty sure it's a bug. When subnet mask is 255.255.255.0, I can't save a destination IP that doesn't end with 0. Or rather, I can, just the zero overwrites the digit on save. It dousn't mangle the digit using a different subnet, 255.255.255.255. But I can't then go and change the router subnet to that in the LAN settings - so my devices remain on .0 and the rules have no effect. Saving 255.255.255.0 in LAN settings, results in the form validation saying my router IP 192.168.0.1 is invalid! So another bug perhaps too.