hi, there are many Crypto hosting providers available on the internet, some of them are;
1: Hostinger
2: MonoVM
3: Hawk Host
4: Namecheap
5; Namesilo
and many more are there, hope this will help you
The Android Apps are generally written in JAVA, and IOS application is written in the Swift Language. many of the developers choose IOS over the Android just because of money, the Complexity of iOS app development is less complex compared to Android app development.