This might be difficult. With iOS, Android or Windows you have to trust the OS Vendor. I assume especially on iOS it might be difficult to supply any meaningful encryption at all if Apple decides to not supporting it.
Android is open source so if an OS vendor outside of the United States decides to use it and provide strong encryption there is very little stopping them from doing so. A lot of the hardest work has been done already.
There is a small but growing market for strong encryption. US companies will find themselves losing some amount of market share due to encryption restrictions. We already saw this once with the previous crypto wars. The U.S. thought that they could corner the market on good crypto and instead ended up losing a good portion of the market. The U.S. lost that war and they can totally lose this one for the same reason. We don't have a monopoly on good crypto in the U.S. and if they have their way we'll end up with only bad crypto.
This might be difficult. With iOS, Android or Windows you have to trust the OS Vendor. I assume especially on iOS it might be difficult to supply any meaningful encryption at all if Apple decides to not supporting it.