Q.Meyers Zoysia Really bad shape
Meyers Zoysia sodded 2 yrs ago. It’s in bad shape and full of weeds with bare patches. Last season it was cut from 3′ to 1′ or less after no mowing for a long time. It was not doing well when in season. Now dormant (Atlanta) it’s full of weeds and bare spots. It’s in full sun. There appeared to be no fungal disease. It’s in rich soil. Little fertilizer was used last season. I’ve sprayed weedkiller only where weeds are thick, totally covering the grass. I’ve spread anti-germinating stuff twice (natural corn-based). What can I try? What do I do? Have I ruined it?

Certified GKH Gardening Expert
It is possible that you may need to re-seed or re-sod the lawn. If the amount of time and effort to eliminate the weeds would be greater than re-doing it, your efforts are better spent redoing it.
It sounds like the lawn may have been stressed after getting too much of a cut. When many plants lose more than 1/3 of their size in one go, it can stress them. A stressed lawn a much more susceptible to being invaded and pushed out by weeds.