Hi

This is very much still a work in progress, but you may want to try:

1. In the address bar in Firefox for Android, type about:config
2. Search for network.trr
3. Tap the field under network.trr.bootstrapAddress and enter 1.1.1.1
4. Tap the 0 under network.trr.mode and change the number to 3

This is taken from https://blog.nightly.mozilla.org/2018/06/01/improving-dns-privacy-in-firefox/. The mode 3 I mention above is to fix DoH regardless instead of the mentioned mode 2 that will revert to insecure DNS

This is a more technical response, so I recomend you tread very carefully before changing entries in about:config.

Thank you for your quick and very clear reply. I followed your instructions, and it seems to work, but I have no idea how to test it. I have tried to set up all my devices to use opendns, but since those queries are unencrypted, my ISP can still sniff them out. The idea I could keep their noses out of my business is gratifying. Thank you.