I've got a 6th Gen iPad, running 12.4. After updating to this version, it broke Litchi. DJI released a new SDK for developers (like Litchi) to correct this problem. So, after installing the new version of Litchi (2.7.0), it all works great again.
While I don't have iOS 13, I can't comment on it.
But my question always is, why upgrade if you don't benefit from it? If it isn't broke, don't fix it.