For some reason, that instills terror in me.
But it's reproducible builds that scare you?
It's part of the glamour that Apple has built around its products, but it is mainly a marketing thing. After all Cellebrite and Pegasus manage to break through just fine.
The big benefit though of reproducible builds is that what you see in the code repo is actually what you get on your device. There is no reason to hide this code like Apple do, it's not 'magic' and having visibility helps against apps abusing the users' data.
Verifiably open source packages are a net positive to security because it ensures the code running is the same code that has the public's eye on it.
People keep forgetting this, because they spend most their time thinking about security in the terms of a enterprise system, but for a personal usecase, an app extracting data to their servers that i was not expecting is a info leak security breach.
Its just that acknowledging that fact requires treating most operating systems (ubuntu, (but not debian) android, and ios included) as malware and this is a uncomfortable position.