I believe I have the same issue. I have a Galaxy S21 Ultra with the original s pen, not the s pen pro. It says it's on in settings, but my phone will not detect any movement or touch from it, seemingly after the update. Hope this gets fixed soon!
@Chris Mehl: If you place the S Pen in it's holster, then head to Settings > Advanced features > S Pen > Air actions > Tap the 3 dots in the top right > Reset S Pen, does this resolve your issue?
I cannot get mine to work it's so infuriating
Mine does not even show that option it only has an option to try & connect an s pen pro