Bringing Spider-Man in a Disney+ show was still considered a bit impossible when The Falcon and The Winter Soldier was being produced. But when you think of Spider-Man, Sam Wilson & Bucky. One thing that comes to your mind is that airport scene from Civil War followed by Anthony Mackie teasing Tom Holland in different occasion.
Well the Finale of the Falcon and the Winter Soldier took place entirely in New York which is the hub for many MCU characters including Peter Parker / Spider-Man. In an interview with TFATWS' showrunner Malcolm Spellman, Inverse had asked if they had plans to include Spider-Man in the finale. Malcolm Spellman reveals that he had, only to be stopped by Kevin Feige.
Malcolm says "Of course! Then Kevin Feige tells you, “No. Stop it.” Listen, when you first show up to these projects, in your mind you think you’re gonna get to use everybody in the MCU. But Marvel always asks, “Does this person belong in this story? You cannot just geek out and put all of our characters in your project because you like them. They have to occur organically.” So Spider-Man did not make it."
Considering the story of TFATWS takes place before Spider-Man: Far From Home, the cameo would have still linked perfectly without altering the ending of Far From Home. Too bad that it didn't become real. But even without Spider-Man, the story of The Falcon and The Winter Soldier end well.
(Source - Inverse)