I still get the same speeds as before. But I have noticed that their cell towers are heavily congested in some prominent areas of central mumbai, which refuse to work even now. I get full bars in those areas, but data packets don't move at all. I have tried complaining to CC, but they had no idea what I was talking about. As per them, "if you get network, internet will work". Don't know whom to escalate this to.
And yes, there is no way to change APN settings in iOS devices. Those settings are locked by Jio.