There seem to be three ways to approach this:
1) Perhaps you've not done the research (which is kind of hard to believe), and this is just a business decision. You want to keep enrolling students, or keep your admit rate high, and you'll take a gamble on other's research
But there is an operational issue, too. Let's say you admit freshmen for Fall, 2021 without tests (good for you).
Your application for Fall, 2022 will open in August, 2021, before those freshmen enroll.
You won't have any research or data for at least four more months, and more likely, a year. But you're going to stick to the SAT?
How you gonna keep them taking the SAT once they've seen test optional? How you gonna keep them down on the farm>
Of course, students with privilege will do it. Because it benefits them.
Again, this calls for EM Leadership. You know you'll do it if @Stanvard_U does.