I want readers to know that your headline claim, "Signal's servers store no contact lists at all", should be coupled with the important caveat that believing that claim still requires trust in Signal and Intel personnel/servers.

And even if someone, like yourself, assumes such trust in Signal & Intel, the metadata protection Signal does offer still requires other metadata tradeoffs. That's not 'equivalent' to other options, it's different in notable ways. For some users, like say an anonymous whistleblower without a 'burner' phone number, Signal's metadata handling is arguably worse than other extant options.

You find Signal a preferable, perhaps even dominant choice; I think they're a mixed-bag once aware of all the tradeoffs.