Ari-Soft may not have an ETA for Joomla 4, but Joomla sure does.
But it turns out that I can't even wait that long. My hosting service will be ending standard support for PHP 7.4 in a couple of months (which means that if I stay on PHP 7.4 they charge me extra.) So, time to update to at least PHP 8.0. And guess what? ARI Datatables breaks.
That was the last straw. I've run out of time. I've coded my own solution and kicked ARI Datatables off my site. Datatables been a good product and served my needs for many years, but in the immortal words of Darth Vader, "You have failed me for the last time."
Buh-Bye.