I remember the buzz of having Spider-Man join the MCU before Captain America: Civil War. I hadn't read that particular comic book, but a lot of the nerds I talk to and respect told me that Spider-Man was pretty crucial to the storyline. Please note that these are the same nerds who also stood up for Adam Warlock being crucial to the Infinity War storyline (which I had read and was familiar with), yet that character was completely written out of Infinity War and Endgame and no one noticed because the storyline didn't follow the books, yet was still quite good.
So knowing all of this...and then having watched Captain America: Civil War...I'm still not certain that Spider-Man was necessary at all. I don't think he was necessary for Infinity War or Endgame either. Don't get me wrong...I like that character and I think that he was a great inclusion and lightened the mood in several spots, but Spider-Man was never essential to Captain America: Civil War or any of the others he was in. I mean...what did Spider-Man even do? Take away Captain America's shield? Give Iron-Man someone to mentor and miss after the snapture? Help fight Thanos on Titan (which they ended up losing anyway)? All of those things could have happened through another character, easy. The only thing he was really good for was having a teenager to rope other teenagers into wanting to see the film (because they had a character that represented them).
Anyway, I guess my point to all of this is that Spider-Man going back to Sony seems like a good move at this point. It means Tom Holland will probably appear in the next Venom movie and that his appearances in future Avengers films will depend on Disney showing up with a truck load of cash, which they probably won't do because...why? I think I prefer the smaller plotlines anyway...where Spider-Man faces off against one of his rogues' gallery villains and they expand the world just a wee bit by exploring various characters Peter Parker interacts with. I will miss Happy Hogan, but I'm sure they'll have fun with the Aunt May character.