there are many factors and theory of signal is not linear .So you always make balance to have the most gain.
But beyond everything you can coded more data on higher frequency at the same time slot and having same channel width.
There is also modulation which have impact but I dont know how DJI does it.
So in theory camera view(phone) during flight should be more stable and clear when you use 5.8G but only for short distance because for larger 5.8 is jus not reaching (at the same power output as 2.4)
if you are interested so much, I encourage you to technical manuals on radio signal transfer theory

I graduated my university above 15 years ago and I am happy with that.
Unfortunately in my brain remains maybe 5 % of this knowledge