I can imagine an alternative finale for Black Widow, where instead of breaking into a ludicrous sky fortress, she instead has to sneak into an underground facility Mission Impossible-style. I would have liked to see some heist shennanigans; deadly traps, security measures, gadgets. They could have gone all out with this.
But it seems they had only one idea: Black Widow sliding down the side of a crashing fortress. It was all over every trailer for this movie. It felt like they had this sequence finished before they had shot a single scene, or written any story.