How to set DoH on Vivaldi
Upgrade your Vivaldi to latest version
Make sure you have installed latest Vivaldi, or you can download here (opens in a new tab).
Go to Settings
chrome://settings/security in address bar, it will automatic redirect to
vivaldi://settings/security, however, you can't use this URL directly.
Set DNS.SB DoH Server
Advanced section, enable
Use secure DNS, choose
with Custom and input: