The Chromium itself is still patched to disable data collection and opt-in metrics according to the developer and since it uses Vanadium patches I could attest to that. Always better to use the Chromium as a base and build with own patches rather than centipeding someone's fork like ungoogled-chromium. Since if they delay, then you delay.

These forks also aren't security hardened like Vanadium is, forks will just amateurly take out anything that mentions Google which leads to some regressions.

Secureblue is not endorsed but both have a similar user share and the maintainers are frequent GrapheneOS community members. It's listed as an example of other OSes using hardened_malloc on our site.

It's usable, but hardened_malloc will break certain apps the same way they do on GrapheneOS for security. Electron apps are an example. I don't daily-driver secureblue though and the barrier for entry is higher than it is to get started with GrapheneOS.