You had good GPS reception from the moment you engaged the motors. However, your home point was not recorded until 23 seconds into the flight which means you did not wait for the home point to be recorded before taking off. It is always recommended to let the drone capture its home point before taking off.
You flew down from your launch height into that area above water. At 1:48 into the flight “Auto Landing” was triggered and the drone began descending.
At 1:54, you pressed the RTH (Smart RTH) button. However, that command was ignored due to the fact that your drone was already in “Auto Landing” mode. You continued to press the RTH button many times but those commands were ignored by the drone.
So, the question is: Why did your drone go into “Auto Landing” mode?
According to the DJI Fly Safe web site, you were in a Blue Authorization Zone:
Much of the southern half of Malta in in this Blue Authorization Zone. Have you flown there before? If you have, you would have had to make an “Unlock Request” and loaded the unlock code into your drone using DJI Fly.
As best I can tell, the reason your drone automatically landed and didn’t let you regain control was because well into your flight, the drone detected it was within an authorization zone without an unlock code and DJI’s remedy for this situation is to auto-land. This would have happened whether you were using DJI Fly, Litchi, Dronelink, or any other software. In a situation like this you can slow the descent of the drone by pushing the left stick forward. However, since you were already below the launch point, you would have not been able to save the drone using this method.