Serious question: Would it not be possible to build an adblocker that is not browser based but installable? The browsers control what they allow to be loaded (extensions, add-ons). They are forever changing internally. If the blocking was outside the browser, they could do nothing about it. Yes, a type of proxy perhaps, whereby the stream was filtered. Could a type of uBO or similar be created that has lists to filter all traffic through the program?

DNS ad blockers like Pi Hole and AdGuardHome have been around forever. However, in non-free browsers like Edge and Chrome, they can (and do) play all kinds of tricks such as hardcoding DNS servers, cert pinning, fixed DOH routes, etc. which means it's only a matter of time until those stop working as well.

Pihole?

I've ran a Pi-hole for years, but increasingly there is 1st-party content and Pi-hole cannot handle this. Likewise for YT videos. Pi-hole cannot handle this issue.

That wouldn't block crap that is delivered from the same domain as the content, or stuff delivered within the content itself, like embedded ads, or even content advertising (where the content itself is just advertising).

This same conversation is being held about Vivaldi as well, as they are subject to the same thing. Unless and until people move en masse to Firefox or other, the monoculture invites abuse by those who control it. This is the new milieu of control.

FreeTube works very well for watching YT videos. They have adblock and sponsorblock. You can subscribe without logging in. You stay out of the ecosystem as it were.

This is a cat and mouse game. The overarching issue here is the web embraced the monoculture of Chromium as the basis for browsers. Can we really expect any less?

I've had good success with Violent Monkey and scripts from Greasy Fork on every browser I run, which is Edge (work becoz SSO), Chrome, and Firefox. They have never been detected.