yes looks good on paper.
I use the X4s, which has very similar specs, just lacks Dynamic Range (11.6) and the ability to switch lenses. This can be great if you have a altitude restriction, you can use a wider angle lens,
Yes DJI GS Pro supports the X7
The bigger lens also can be nice in my opinion. I notice less lens distortion when using bigger lenses. But calibration can help with that.
With my current rig (X4s, m200 and a on board PPK system) i am achieving max 12cm vert error at 120agl
I think it would be better than the X4s, but would it be worth the price difference and limited platform, maybe not