Can’t speak for Florida but some power companies and some states really frown on combining a battery bank with a grid-tied system. Makes a lot of sense to me, too, to have a charged battery bank ready and waiting along with solar but Duke Energy does not allow it here in NC.
Doesn’t have to be a grid tied system.
Wire it the same way a UPS back up system, automatic shut off of mains circuit with backup kicking in. Mains circuit stays off until manual reconnect.
Surely data centers and others have such in place, so maybe Duke has objection to the feed back into the grid part only.