Link to log files uploaded here - https://ufile.io/f/3o92p
Just a real quick initial look at the .txt file, it appears that you may have crashed the aircraft into the ground or an object. You were flying at full elevator at a speed of ~18ms and issued down throttle at the end of the data at an altitude of 7 meters. Will look a bit more, but initially that is my thought.
Below is the flight profile from GE. As you will notice the aircraft altitude was continually descending accross the lake up until you lost downlink. That being said, as I mentioned above at the end of the data you were still issuing full down throttle. Assuming that down throttle lasted an additional 2-3 seconds ( Which cannot be confirmed due to downlink loss) the aircraft would have crashed in the water. I do not see any errors that can explain otherwise.