First of all, thank you for thinking ahead of the game and all your great work!
Small Q, is your implemented option to prevent Firefox using DoH in the Alpha 2? (I suppose its there) For my testing on the Alpha 2, i enabled DoH on Firefox and then find myself on their CF DNS. My vpn is set to exclusive with DNS filter set to Router and DOT is enabled. I can disable DoH in Firefox for now, but with any future update from Firefox, I will forget to check if DoH is enabled by default. I rather have my DNS for choosing. Due to the inconvenience not able to SSH in the router to add your recommend line: server=/use-application-dns.net/ in /jffs/configs/dnsmasq.conf...... Just wondering if I get it right.
Thanks!