So, in short:

• Google is not killing ad blockers, but merely chopping off both legs and arms in the name of security.
• ublock Origin is implementing a lite version for chromium browsers, supposedly being pretty decent given the circumstances.
• Old Manifest V2 extensions will be disabled in June 2024 and Manifest V2 will be removed in June 2025.
• Firefox is Firefox.
• Privacy and security focused chromium based browsers will have to implement proper native ad blocking.