So I think the “let him have his fun” line before the Hulk fight insinuates Thanos was legitimately just letting Hulk get a few hits in before “having his fun”. But this is all going deep into theory at that point.
I also don’t know if the stones actually augment Thanos’ physical strength, so I’m also making an assumption there. I just kinda assumed the more stones he had, the stronger he is. The music (when Thanos teleports into Wakanda) is what led me in that direction.