Some of the descriptions of Drax's strength seem to be hyperbole. Although he is a stud, he has never been anything near a match for Thanos. They really aren't in the same league; Odin blasted Drax into unconsciousness with ease...his same attack didnt make Thanos flinch.
About Juggernaut taking a decade to crawl out from under a mountain: When he first became the Juggernaut the cavern he was inside collapsed on him...took him a decade to crawl out unless Im mistaken. It also took him a month to get out of the that concrete foundation the time he got beat by...Spiderman 🙁 I imagine Champion would have just clapped his hands together in either case and free himself in the process of destroying the landscape.
Thing had the best showing against Champion because he was the best fighter there, the most disciplined, the most prepared, the strongest of mind and body. In my opinion Thor and Hulk would have also given him a good fight. What boxing has to do with i dont know...as far as I knew neither Ben Grimm or Colossus were formerly trained at boxing in particular although they have been formerly trained other combat techniques. Thing also managed to put up a good fight and even break some of Champions ribs. Did Colossus get a punch off?