IMHO, Thanos is nowhere near Superman physically. Neither do I think these are either: Thor, WM Thor, and WM Thor with power gem (the gem does nothing). Thanos has great agility, good reflexes, moderate super strength (most likely less than Thor), and decent physical blunt durability (not great though). For these reasons (especially the agility and reflexes) Thanos is able to seemingly embarrass others physically.
Big misconception
1. X is just as strong as Y since he was shown to go toe to toe in a fight against Y.
This is faulty because it assumes that one cannot be hurt by less strength than their own. It is also faulty because it assumes that since X has the ability to knock Y away then X's strength is in the vicinity (or much greater) of Y's. This totally ignores the comparative strength of the attacker vs. the weight of the foe.