@miyukiwork Hello, I just tested it in Opera Android app. It is working. I suggest that in addition to Cloudflare and Google Public DNS servers, you add OpenDNS 220.127.116.11 and Quad9 18.104.22.168 by default as they are the 4 most popular. Also, I ask you to release the DoH feature for Opera Mini (android) as well. Thank you.
Suggestions and feature requests