So I have been thinking about MCU Hulk, specifically his strength and ability, from The Incredible Hulk all the way up to Spider-Man: Brand New Day and before I get into it I just want to say it's just a theory.... A filmmm theory 😂😂 ok moving on swiftly.
I think that instead of the classic "gets stronger as he gets angrier" mechanic from the comics he actually gets stronger after his battles and experiences.
In the 2008 film, Hulk barely beat Abomination. To be honest, he really was not all that strong, and he was not that fast either. He was also getting cut by high-caliber rounds and that helicopter collision had him covered in cuts and blood.
Fast forward to The Avengers (2012), and his durability is far greater, with high-caliber rounds just bouncing right off him (literally just pissed him off more). He is beating up Thor, he is strong enough to kill a Leviathan with one blow, and he moves so fast that he is a blur.
Fast forward again to Age of Ultron, and his jumping ability has improved significantly as well.
Touching back on the "gets stronger as he gets angrier" ability, I think that is something he might have lost after the 2008 movie.
That was the last time we actually saw him get stronger mid-fight because Betty was in peril, which made him angry enough to overpower Abomination but it burnt him out so a different method was created.
Instead, I think MCU Hulk gets stronger after he transforms back into Bruce. It works almost like how your body builds muscle after damage in the gym. Once he recovers and transforms into the Hulk again, he is easily able to overcome things that hurt him in the past.
So it's like every Hulk out is a gym session, he gets hurt, does crazy stuff then goes back to Bruce as his recovery period then when he comes back he's faster, stronger and better. I don't think in another 1v1 Thanos is getting another clean victory