Looks like pilot error to me, IMHO. The system told you to come home at 21:58. You directly overhead and you didn't come down from 200' prompt enough, you took too long to descend. I think you may have been thinking, I'm already home, since you were directly overhead. But that's not true, that notion is flawed. Being home is on the ground, not high overhead.
You do realize that full left stick down is OK, the craft will not turn off the motors while in flight with full down left stick. To descend faster than that, fly forward at about 10-15mph and turn full right (or left) while left stick is full down to descend, in a toilet bowl method. That will let you get down really fast, but you need to practice that to learn this tactic.
Bottom line, you had plenty of time to descend 200' when the warning appeared. You simply didn't act prompt enough, with adequate vigor to get yourself on the ground. A good practice is to never let the RC give you an RTH warning for low battery. Pay attention to the battery level at all times and get yourself on the ground before you reach 20%. If you do that you won't have an issue.