I count 4 SHWs who are fairly concencus top 25 ATGs: Bowe, Lewis, Vitali and Wlad. Between them, they've had 9 official losses. Apart from a very debatable MD loss by Bowe to Holyfield, and an injury induced loss by Vitali to Byrd, all of the other losses by SHWs either came at the hands of other SHWs, or by smaller fighters with power who stopped them(2 and 5, respectively). ALL those losses were also much more definitive than the two losses to smaller, slicker opponents. If you're trying to evaluate logically, taking personal bias and favorites out of the equation, this is very strong evidence that being a smaller speedster and slickster is not a recipe for success against modern SHWs. Take it for what you will when deciding which historical ATGs would have the best chance against modern SHWs, as well as what fighters around today are most poised to beat the current champs.
Nobody wants to try to come up with a reason why this doesn't indicate that Ali or Usyk couldn't beat an ATG SHW?