Q.Product to kill bermuda grass in flower beds
Is there a product to spray over landscape plants that kills bermuda grass? Some years ago, I thought I had a product “Post” but cannot find it.

I would recommend pouring boiling water on the areas where the bermuda grass is growing. Boiling water will kill whatever it comes in contact with. This article will also help: https://www.gardeningknowhow.com/plant-problems/weeds/how-to-kill-grass-naturally-kill-unwanted-grass-in-your-yard.htm
Alternatively, you could cover your garden plants with cardboard boxes or use a gallon milk jug with the bottom cut off as a shield. Spray the grass with an herbicide when the grass is actively growing. One application won't work, as it's going to take several.