So let’s say there are no transformers in between building loads where the power produced by the solar inverter is produced and those loads consume that power from solar are unbalanced then that unbalanced current what’s to stop it not return back to solar inverters neutral?
The inverter measures the voltage of the respective lines. For simplicity, let's consider just a single phase inverter that operates on a 120/240V grid.
It measures line 1 at 121V. It measures line 2 at 123V. This slight difference in voltage is what is existing, as a consequence of the existing imbalance of loads. Different amps drawn on the two lines, means different ohmic drops on the service conductors that deliver power to the premises. And therefore, slightly different voltages on each line at the point of interconnecction.
Based on DC power available to the inverter, suppose it "wants to" provide 6 kW or 25A of current onto the building distribution system and utility grid. The resistance between the inverter and grid at the point of interconnection is 0.08 Ohms. Through a trial and error feedback loop that solves the algebra problem, it detects this resistance and determines that it must exceed the grid voltage by 2V on each line in order to output 25A. It then produces a voltage on line 1 of 125V, and an opposite phase voltage on line 2 of 123V. This voltage difference produces equal and opposite currents of 25A.
The inverter only offsets equal and opposite currents of the premises load. Any imbalance in the loads on the premises, must be supplied by the grid-forming device, in this case the utility's transformer with a centertapped secondary. Grid-forming battery-backup inverters are commonly built to work with autotransformers, that convert their single phase output into a split phase grid that can supply the imbalance as well.