There has been a remedy for crabgrass on these and other forums for about 15 years. I believe it works against dallisgrass, also. You only need baking soda, water, and a drip of shampoo...and an old or new sock or stocking. You can try it and see how it works.

Put a tablespoon or so into the sock/stocking.

Put a few drops of any clear shampoo into the water and put that into a spray bottle.

Spray the dallisgrass to see if the water beads up or forms sheets on the grass blades. If it beads up then add a little more shampoo. The water has to form a sheet on the grass blades for this to work.

Once you have the water/shampoo adjusted, take the sock of baking soda and squeeze it right over top of the wet dallisgrass. The purpose of the sock is to make an extremely fine powder to get stuck to the wet grass. By the way, DO NOT GET THIS DUST IN YOUR EYES. It's not harmful, but the pH difference from your tears is like pouring shampoo right into your eyes. You'll want to flush with lots of water. Also don't inhale the dust. It's a good idea to wear a full face mask. I'm speaking from experience here. So I know this works on crabgrass and the baking soda does not affect St Augustine grass. It probably does not affect bermuda, but I can't be sure. Assuming the dallisgrass does die in the next few days, try flushing the area to dilute any remaining baking soda. It's not great for the overall health of the soil.