It doesn’t really matter what kind of block it is. Vivaldi comes with TLS (Transport Layer Security overlay), but it is not necessarily turned on if its an old install. If a fresh profile has it turned on, then all traffic leaving the browser are encrypted and cannot be tampered with. you can check if it is turned on–

go to Vivaldi://flags

Vivaldi has TLS active by default at some point for new installs. If new profiles also have that then that’s what is happening.

The browser is not using the ISP’s or the computer’s DNS settings. So DNS blocking/redirecting won’t work on it.

there’s the ole https://www.reddit.com/r/darknetplan/

kitschy name, but when it was established it was not even planning anything like what it is doing now. meshnet is the section you’re looking for.

There really was some ads that get through last month, but UBO fixed that last week. Either you got lucky or you are not in that set - Google do A/B updates before.

randomly came across these, so yeah.

edit: about this apparently https://archiveofourown.org/works/54711364

They have for public benefit program where they give out their paid security tiers for free? If you can get recommended into it. Build a lot of goodwill there for non-profits community.