FWIW I've been using https://gitlab.winehq.org/wine/wine/-/merge_requests/4809/diffs?commit_id=e0... for the past 6 months. It really could ship as-is. It has been precise and behaving exactly how I want.
It turns out Windows behavior is not consistent. It seems to differ across different devices/drivers. Some touchpads have inertia. Some don't.