How do you link an existing account to Google SSO?

Excited by today's blog post about remembering your preference for SSO, I went and logged out of some website and unlocked 1Password in the browser to log back in.
I tried:

1. DigitalOcean via Google
2. Geoguessr via Google
3. ITAD.eu via Steam
4. Notion via Google
5. Itch.io via GitHub

None of them popped up anything from the 1Password browser extension like in the video. Is there a setting I need to enable?
I have 1Password entries with just a note saying "Use Google SSO" for many sites. Will it not prompt to update if I already have the site it in 1Password?

1Password Version: 8.9.8
Extension Version: 2.3.8
OS Version: Windows 11
Browser:_ Firefox