Honestly the easier way to switch from solar DC to grid AC is to just have a flywheel between the grid and the solar power plant. It might not be as efficient as a capacitor bank or super capacitor bank but it’s dead simple to implement and it’s extremely reliable.
ideally you wouldn’t want it in between, but beside, you would implement it as a “frequency smoothing” device, along side production, probably at a factor of regulation specified amounts.
Modern solid state conversion is very efficient and highly effective, it’s just not great at the inertial problem, though it can be mitigated. It’s just not as clean.