This article got the trr.mode key slightly wrong

0 - Default (will be one of the below options, right now it happens to be 5)

1 - Race regular DNS and DoH, use whichever one responds first

2 - Try DoH, use regular DNS if DoH fails

3 - Use DoH, regular DNS is disabled entirely

4 - unused

5 - DoH is fully disabled, always use regular DNS