Continue with the drowning and squishing. Perhaps also flicking into soapy water.

Stink Bugs, according to all the research I have seen, are pretty immune from most all pesticides although pyrethrins seem to be the most effective, and the synthetic pyrethroids seem to be even more so. Since pyrethrins are very broad spectrum poisons due care in use, to protect our pollinators and beneficials, is important.
Knocking these buggers into a bucket of soapy water, preferably early in the morning when they are still sluggish, can help. Where these buggers are known to be Floating Row Covers can be of some help as well.

thanks, I'll proceed with the dish soap. Row cover would not work on okra--they grow to 10-12 feet high! Same with corn--too tall/big.

I was hoping others were experiencing the same and had ideas but apparently not many people are growing okra in stinkbug territory! As the marmorated stinkbugs move south though, they'll be a lot more.

thanks for the advice