#Signal was as secure as claimed, it would've been shut down like #EncroChat, #SkyECC & others...
Just stop the BS. EncroChat was specifically built and marketed for criminals. It wasn't shut down by law enforcement, it was hacked by the French police, after which they decided to shut the service down themselves.
Signal is open source (and the issue regarding reproducible builds is known, but it doesn't impact the security of the app. It is caused by a navigation library that causes some race condition during the build process, the result of which is dependent on CPU speed. They are aware of the issue, and are working to fix it. It is tracked here: https://github.com/signalapp/Signal-Android/issues/13565). If you don't trust the official build, you can compile it yourself. There are also forks like Signal-FOSS or @mollyim available if you prefer that.
The server is also open source (of course you can't verify if they are actually running that code, but that's gonna be the case for every application with a client/server architecture. Your point regarding Signal being "proprietary SaaS" is, again, total BS.
