Cool season grasses are far easier to control weeds just by the height of the crop and training the roots to grow deeply and be drought tolerant. You don't have that ability. Spring pre emergence seems to be the best 'control'.
How big is your lawn? How infested is your lawn with crabgrass? I would be more inclined to do very surgical removal using glyphosate. Wear rubber gloves, have a rag for excess, dip fingers in glyphosate and wipe on a few leaves of the crab grass. Just a few of the blades of a clump of crabgrass. I always use a shield for accidental drips from your fingers such as a tarp as I move through a lawn. You should wet only enough to transfer a little wetness of glyphosate to the vigorously growing leaves of your crab grass. The entire plant does not need to be treated, just a few leaves. No dripping applications necessary or smart.
Do this when there is no chance of rain for a few hours. The glyphosate is systemically transferred to the roots where it kills the entire plant in three weeks. It dries right away and is then not transferable to any other plants.
This wipe on glyphosate technique is very specific. You should see some wilting in a day, complete kill in 3 weeks. Mow weekly. What is still obnoxious and glowing yellow or orange in your lawn I would pull up, dig out.
Plan to do another application in a month after the first month of kill. Before winter. I'd continue with this technique and stop doing the pre emergence in the spring. You could also use a paint brush but my fingers made less mistakes. You will see any drip you've made.
Need to see pictures and have more information about your practices so that you will not have to do this on a regular basis for control. You can plant on doing at least two applications this year. Another two next year. What is happening with neighbors?
If they allow their crab grass to flower and pollinate the entire neighborhood will be reinfected every season. Preemergence herbicide is gnarly. You shouldn't have to use it for regular maintenance. Cool season lawns are far far easier to maintain with no use of pesticides ever. Your Zoysia is actually a creeping weed with shallow roots just like other weeds. Ugh.