Any Free iOS app store to upload tw app?

Apple’s devices are good, but developer service is very bad, they reject my app upload due to “one or more reasons”.

I’m now going to upload TidGi mobile app to (a parite app store), The TidGi mobile app on it will be free (and also Free for me to upload). I will upload to real iOS app store whenever Apple allows me to do, but it will also charge some money to pay for Apple’s 99$ annual fee.

I’m not sure if there is an alternative Free iOS app store for English users, please recommend if you are using some of them.

Maybe testflight is useful, but it’s not clear exactly.