Ironically, Signal actually ranks a -1 for privacy in this use.
Presumably you're already using Signal and getting mainstream contacts to start using it too. You probably have a basic profile that at least includes your real name, and might also have your picture. Maybe you're even one of the 7 people in the world that use the Stories feature in it. Well good news, now all of that is also unconditionally available to anyone in any group you ever join, including any future changes you ever make to that info, unrevocably forever into the future.
Signal has a fun dark pattern where it unrevocably grants permissions for anyone you allow to contact you to see everything in your profile for the rest of time. It has only a single trust level with contacts effectively: full trust.
This is unacceptable in any tool you use for online community, unless you exclusively use it for online community and can decline to provide any info in this full-trust level. Unfortunately Signal also makes very sure you can't have a second account, by tying your account to a phone number, and only allowing one Signal instance per mobile device.
Is Signal good? Yes, but only exclusively for communication with people you already trust.
EDIT: typos