Etydhv

In Avengers: Infinity War, Thanos can

badly hurt The Hulk

so we know that his punches are lethally powerful. However at the near end of that movie, when

Cap attempts to hold Thanos' hand and gets a punch to the face

Why doesn't Cap's face become a mess or have any crack in his skull?

Again in the fight scene near the end of Avengers: Endgame,

While Cap is lying on the ground, Thanos punches seriously at Cap's face. Given that version of Thanos is crueler in this fight, and doesn't seem to hold back his power like in Infinity War.

Although Cap is a super soldier, I don't think Cap's body is more durable than Hulk. If Thanos' punches can hurt Hulk, I guess they should blow up a normal person's head.

In addition to the effects of the super-serum that gave him his abilities, at the time in question Cap is holding Mjolnir. It is well established in the comics and MCU that the wielder of Mjolnir gains the power of Thor.

Whosoever holds this hammer, if he be worthy, shall possess the power of Thor.

_{Thor, The enchantment placed on Mjolnir.}

Asgardians are continually shown to be extremely resilient to physical damage, Thor more so than most. Given the stacking and interacting of powers and abilities as well as Steve's own force of will it's no surprise he was unaffected. Imagine punching a hellbent god on super steroids.

The super soldier serum that was used on Steve doesn't just make him stronger and more resilient but also gives him regenerative powers.

Steve Rogers: Dr. Erskine said that... the serum wouldn’t just effect my muscles, it would effect my cells. Create a protective system of regeneration and healing. Which means um... I can’t get drunk. Did you know that?

_{Captain America: The First Avenger}

On top of that Steve seems to be very badly wounded in both fights against Thanos. In Avengers: Infinity War Thanos actually seems to knock Steve unconscious for a bit.

In Avengers: Endgame Steve, and Tony/Thor, are all really hurt by Thanos but Steve carries on with the fight even though he is hurting. It isn't the case that he isn't hurt as bad as Hulk, it is that when he gets hurt he carries on. This has always been the case since before he was even given the serum and this is what makes him worthy.

Also note that Steve has survived falls from great heights before throughout the films, not always landing on his shield, so it is safe to assume he is more durable than you are giving him credit for.

In The Incredible Hulk Blonsky is given an incomplete form of the super serum that Captain America took, with it he takes a full body kick from the Hulk that sends him flying into a tree and mangles his body. He's up and about a short time later. Cap with the full serum is more resistant, even if he was hurt his healing factor would mean he wasn't down long.

If you think about it, between Gamora's death and the snap, Thanos doesn't kill anyone. He wanted the snap to take the lives of everyone so that he had less guilt. He was probably holding back against everyone since he didn't kill war machine or black widow despite having the chance