All right let's take a quick look.
The volume of your room is 2880 ft^3 (81.55 m^3). The T30 from your measurements is 210ms. So the Schroder freq is 2000 * (T30/V) = 102Hz. The transition zone ends at 4Fs, so 408Hz. Using this information I have drawn a couple of lines in your FR. You expect everything above the transition zone (408Hz) to mirror the published in-room response of your speaker, and here we see a problem - a rising treble response above 3kHz.
You did not say what speaker you are using, so I can't google for a published measurement. But there is a possibility this could be a measurement artefact, e.g. using the mic at the wrong orientation with the wrong cal file loaded.
This is a vector average of your main speakers with no sub (purple) compared to the actual measurement of your system WITH the sub. I am doing it this way to avoid having to post too many graphs.
No sub vs. sub is to show the effect of the sub. It looks as if your sub is rolling off too early, about 40Hz. Unless it's a very small sub, it shouldn't be doing this. It is more likely that your sub is poorly placed in the room.
There is a dip in your FR at about 200Hz. This is likely SBIR. If you want to diagnose it, push your speakers closer to the wall and see if it shifts upwards.
Above 2kHz, it appears that the vector average of both speakers CURES the rising freq response mentioned earlier. This looks more like what a well tuned system should look like.
The acoustics of your room are quite good. No loud reflections in the Haas fusion window.
The RT60 is well below the tolerance limits for a room of your volume. This would sound too dry for most people and have the effect of reducing ambience and sometimes subjective clarity. But it's also a matter of preference and application, so if you are a studio or if you like that sound, then it's fine. I can tell this room is extensively treated because this kind of low decay time is well below what is achievable without room treatment.
Very impressive!
That subwoofer looks like it's adequately time aligned to the L/R speakers.
The L/R speakers themselves seem to be nice and symmetrical with the heads and tails matching each other and the decay time pretty short.
And the IACC confirms that L/R are virtually identical. This, along with the step response, tells me that they are symmetrically placed in the room.
Overall it's a pretty good result. To do list:
1. Find out why you are losing so much bass below 40Hz.
2. Consider pushing your speakers closer to the wall
3. Find out what is happening with the top end. Place your mic 1m from the speaker, on-axis to the tweeter and pointing towards the speaker, and take a sweep.
