I don't think so. Signal regularly stops committing code to the public repos (https://github.com/signalapp/Signal-Server) when they're working on some kind of big reveal (cryptocurrency integration and such), but the server code is out there for you to run yourself.
Signal has the added benefit that it doesn't need to read what's in the messages you send. It needs some very basic routing information and the rest can be encrypted end to end. With AI stuff, the contents need to be decrypted in the cloud, so the end-to-end protections don't apply.
I meant more regarding their server setup but now that I think about it you are correct, it matters a lot more if the query/message/whatever isn’t encrypted before hitting the cloud.
Signal has the added benefit that it doesn't need to read what's in the messages you send. It needs some very basic routing information and the rest can be encrypted end to end. With AI stuff, the contents need to be decrypted in the cloud, so the end-to-end protections don't apply.