I don't think that question will ever be answered.

If we go by end result: No man has ever been injured the way Jess Willard was against Dempsey: broken orbital bone, fractures, teeth(several) knocked out...

Not saying Dempsey hits harder than Shavers or Tua or Tyson, or Wlad.. hell sounds like loaded gloves, but we dont know that either...so how else can a question be answered without it being subjective as opposed to objective?