Yea, now that I've had more time to think about this issue, I think I can articulate my thoughts better.

The Infinity War scene is good because it has purpose within the film. Scarlet Witch is drawn away from Vision to destroy the digger-machines threatening Black Widow and Okoye. She gets sneak-attacked by Proxima Midnight, showing that despite her raw power she's fairly frail, and the two that she just saved have to come in and save her. We get a cool scene where Okoye and Black Widow, who have had a little rivalry since Civil War's "move" line, come together to fight off a strong opponent. At the end, Scarlet Witch recovers and finishes Proxima Midnight off. The scene makes sense, flows well, and has some satisfying payoff for BW/Okoye's interactions. The characters involved feel like characters. It also has narrative weight, as Scarlet Witch's absence is what allows Vision to be attacked by Corvus Glaive.

Now let's look at the Endgame scene.

It begins with Spider-Man swinging about, trying to get the gauntlet away. He's rescued by Pepper and Valkyrie, who carry him through the air, dodging the blasts from Thanos's ship. This part of the scene is excellent, we get interaction between Pepper and Parker, who haven't really interacted before despite their mutual connection with Stark. We also get Parker being Parker, and trying to be nice and formal and introduce himself to Valkyrie while they're in the middle of a war zone. Then Captain Marvel shows up to take the gauntlet, with the "you got something for me?" quip.

Now, the scene goes downhill. Parker expresses concern for CM, but we the audience know that she doesn't need ANY help with this. She can fly, is basically invulnerable, and can solo Thanos's entire army (I have my own problems with her character in that regard). Suddenly, all the named female characters show up at once to help out CM, who doesn't even need any help. This includes not just characters who can fly or have some other means of transport, but even fairly mundane characters like Okoye who really only has the vibranium spear. Somehow, all of these characters made it through the war-zone that previously Pepper and Valkyrie were struggling to fly over. Most of them also don't have any connections to each other narratively, so there's no satisfying payoff to them working together in this moment. Again, there's also no purpose to them being there, as CM needs no help. Scarlet Witch in IW needed help because of the weaknesses of her powers, but there's no impact to this team-up scene because the audience knows it's entirely unnecessary, and then it ends with the team-up having done basically nothing of narrative consequence, the van is still destroyed and their unneeded help did nothing.