If it is a spur of the moment slug-fest, Mangog wins easily.
As a planned strategic attack, Thanos would probably find a way to defeat Mangog using his brains.
Its always a random encounter unless stated otherwise and Thanos is without his tech here which includes shields and his almighty force block . I'm inclined to say Silver Age Mangog stomps
Thanos has the power to knock Galactus on his ass who is far more powerful than Mangog showing if he can affect him he can really damage mangog. Maker is a cube being who can warp reality yet Thanos dominated her. Mar-vell was far above top tier yet Thanos treated him like he would have the Surfer in the past showing a huge upgrade.
Ah, I see... like Thing or Strange knocking Galactus on his arse?
And like Sentry destroying MM?
Those are the two best 'feats' you present, though no rationale or logic to re-enforce your assertions.
As for the Lord Mar-vell yawnfest, he was an unimpressive monster-of-the-week type villain. I wouldn't take that to be anything impressive or significant. It's like defeating Quasar.
Thanos took on a well nourished Galactus not the weakened one Thing ran into. Thanos also launched him much further. You are really bad at debating. Context always destroys those who seek to subvert the truth.
My rationale is Thanos is powerful enough to defeat beings on par and above Mangog. That is good enough along with him being durable enough to take a reinforced/ctluthonic blade/ig to the chest and walk it off like nothing happened by an entire universe to bring him down.
Mangog was defeated by Thor with a blast inside the mouth. Mar-vell wouldn't even deem Thor a threat. LoL.
See that's why you can't debate you just rehash the same nonpoints over and over again. I told you the difference you choose to ignore it because you're owned and in need of nicotine.
Thanos is more powerful and can survive universal reinforced blades powered to kill the avatar of death. It didn't work. Mangog has no chance.