Google says Manifest v3 is being done "for security reasons" but what they don't say is that it's not for your security.
It's a Judge Dredd situation.
Google is vertically integrating the roles of content provider (ads) and content server so that web pages load exactly the way the page's developer expects them to. This necessarily excludes things that selectively filter content, like blockers.
They're essentially taking an open framefork for the web and replacing it with interactive pdfs, that show exactly what the web developer wants, and collects exactly the information the developer wants to know about you.
If you think you should have more control, use Firefox. Anyone using Chrome is complict at this point.
The only terminal cancer worth mentioning around here is MS-DOS.