Look a little closer. This is a phone measurement. I would hope that the OP at least invested in a semi-decent USB microphone like a
Dayton IMM-6 rather than the phone's built-in mic. Even then, these little USB mics tend to be inaccurate at high frequencies and may not be calibrated. As a minimum, use something like a UMIK-1, preferably a UMIK-2.
The way a measurement is taken matters. If you hold the phone in your hand while taking the sweep, your body will reflect sound back to the microphone. If you point the mic towards the speakers, or towards the ceiling, you will get a different result. And needless to say, you need to be at the listening position.
Also agree with
@staticV3 that this is a suspiciously smooth looking graph, especially without any form of DSP.