At last! Surprised no one is posting about this yet..or maybe I just missed it.
9to5mac.com
UPDATE: I have not tried it yet but users are noting it‘s a dud.

Safari Technology Preview updated with 120Hz scrolling - 9to5Mac
Apple released Safari Technology Preview 135 with 120Hz scrolling support for ProMotion displays on 2021 MacBook Pro.

UPDATE: I have not tried it yet but users are noting it‘s a dud.