i missed the additional step with wifi-direct. That is quite fine so far.
But miracast doesn't work. I can scan and see my TV, but as soon as I try to connect, the zte get unresponsible und after a while, it reboots/restarts the gui. (heavily battery drain) But it needs a complete hardreset, to get the ui back to work.
The feature 'miracast' seems to be buggy. In the next days, I will provide a logcat for the protocol. I do not need this feature in a productive way, so no hurry to solve this.