Who could defend themselves without superpowers ??
In MCU , there are many superheroes with their ability to do imposiible things due to their exposure to chemicals in Lab test , powerful radiation and some got their powers due to naturally by birth. In MCU , there are only few fighters who got their powers by their own practise , skills and self-made superheroes. Among them , few of them are :
1) Black Widow : Black widow has nothing any speical powers that sounds like magical and impossible. She has been trained well and has lots of combat techniques ,skills and strength to kill enemy easily.
2) Shang -chi : He has mastered the Marshal art and till now in MCU he is one of the strongest in hand-to- hand combat.
3) Black Panther : Black panther has lots of knowledge in combat , we have seen him fighting for throne very wisely and strongly.
I think IronMan couldn't defend himself without suits.Thor apart from his magical powers ,he still proves himself worth fighting and powerful in Thor Ragnarok aganists Hulk. Although , he didn't clearly defeat Hulk without thunder powers , he was also defeatless with Hulk. But he still has powers and strength due to being born in God's family. Also apart from this most of heroes like Captain America ,IronMan, spiderman, wanda and many others are not strong enough to defend themself without their powers. While some heroes like Peter Quill and other we haven't seen them fighting without their powers. Since I write blogs mostly by remembering things , I might have forget many heroes here.