Setting aside the fact that we don't actually know what 支援战车 means with regard to role, I would like to know more on how this setup is supposed to fit in the normal heavy CAB with a set of MBTs and a set of IFVs. Does the new vehicle replace some MBTs? If it actually has no dismounts, does it still replace the IFVs? I'm not particularly comfortable with either explanation.
I think this video settles the question of what is that new IFV like vehicle that accompanies the new MBT. It's China's take on BMPT (支援战车).
So most likely the 3 soldiers that was shown entering the vehicle through the rear ramp are the only infantry/drone operators carried. The rest are all crews.
The role is probably regular IFV fire support + front line anti drone & scout.