To be fair, Signal lies about their actual security, particularly regarding metadata protection.
https://passthesalt.ubicast.tv/videos/metadata-protection-in-instant-messaging-applications-a-review/#share
Olvid, a French IM, arguably offers better privacy than Signal, by design. But they are French, so I don't trust them either for the reasons you listed in this thread.
SimpleX Chat (npub1gsu…fy6l) is way ahead of Signal and Olvid, privacy/security-wise.