How to solve Low efficiency at Light Loads in OFF GRID INV and at No load How to eradicate power Loss (i.e) some current flow.

You have to size the power devices for max load, driving up the load and losses they present to the drive electronics and DC supply (switching losses) that appear as a fixed overhead.

You are only going to "solve" this problem with some sort of segmented inverter that operates less of the powertrain at light loads. You could shut down and depower (say) 9 of 10 1kW inverters in a 10kW system -if- they had the facility to synchronize.

Making the thing agile enough to make the transition between (say) 1/10 load and full load acceptably "seamless" is probably doable. You will add complexity, cost and failure-points, and the switch gear imposes conduction losses.

This is where engineering comes in, making the right tradeoff.