I wish Firefox would expose the option from about:config in its user-friendly Preferences page so it will respect the "system default" (the advertised dns server).
I am - for no legitimate reasons - avoiding Cloudflare as a resolver. As far as I know Firefox uses Cloudflare.
I really want to use uncensoreddns.org, but availability has been a little flaky in the past. I'm not sure about Quad9. Google and CloudFlare are obviously out of the question. What else is there?
DoT: dns.digitale-gesellschaft.ch
DoH: dns.digitale-gesellschaft.ch/dns-query
Source:
https://de.wikipedia.org/wiki/DNS_over_HTTPS
https://de.wikipedia.org/wiki/DNS_over_TLS
https://www.digitale-gesellschaft.ch/dns/
Sorry, for not being available in the en-wiki
It really depends what you view as being "trustworthy". Outside of the US good enough? Or do you want non 5/9/14-Eyes? (https://en.wikipedia.org/wiki/UKUSA_Agreement#9_Eyes,_14_Eye...)
Firefox has DoH turned on by default for US-based users. Unfortunately being US-only, it won't protect Thai users just yet. Especially considering the fact that Thai ISPs have known to be hijacking port 53 and NXDOMAIN since forever[1] with ISP in the article being one of the biggest offender.
It might also worth nothing that PDPA, Thailand's equivalent of GDPR, is to become in effective in two days (May 27th) so this incident will be... interesting.
[1]: Starting in early 2000s, with NIPA (that I never see anybody uses), who aim to provide IDN-enabled Thai domain names by providing NXDOMAIN-hijacking services to ISP