Everyone has their favorites and are disappointed if they don’t get to shine in a big team up event. It doesn’t mean the writers or directors hate the characters or want to sideline them. Hulk plays a major role it just doesn’t involve him winning a fight. He was the only one who could use the gauntlet and not die. Vision had to take a L for the story to play out. It’s just how the story was written. It’s nothing against Vision.
It’s not unusual for a character to not use their full power set in service to a story. Imagine if Superman used his full power set in JL stories. Most of the League wouldn’t have anything to do.
I mean honestly Scarlet Witch and Captain Marvel together should have been enough to take down Thanos but did anyone want to see that story?