To be fair tho Parker has lost to SHWs Joyce & AJ already. Don't get this obsession with size at HW.. there's been great SHWs like Lewis, Bowe, K2 , Fury etc.. & great smaller HWs like Usyk, Holyfield, Tyson etc..
Surprised at any marveling about shorter HWs having success when 5'10" Mike Tyson dominated in his day.
Speed, skill and stamina are the keeps to defeat gigantism. As the old Chinese proverbs says. When your enemy stands like a mountain, attack like the sea.