Olvid is in the game since 2019. They have and are close to good cybersecurity French experts. Olvid is used by the RAID (elite tactical unit of the French police).
They are open to bug bounties.
As a startup they have chosen agressive marketing to attract attention and build a sustainable business model, namely with professionals that can pay them. For individuals the app is free, and 4.99€ / month to be able to call people.
A problem raised is that Olvid is using AWS. The Olvid answer is that their security model does not trust the servers.
I think that the biggest problem of Olvid is that it is not internationally mature enough so that people around the world take the time to look into the matter.
They seem focused to conquer the French environment first. They have not survived yet a big exposure at an international scale like Signal so that we challenge well their credibility.
As of now I would not necessarily recommend Olvid compared to the other solutions, just saying that this option exists.