I've been following scoopers and the developments of CBM since the mid 90s, so i've read and heard all kinds of rumors for all kinds of projects and I've seen the ups and downs.
So, I learned a long time ago not to get super emotionally invested in scoops and rumors. At the same time, I also learned not to ignore something just because it doesn't affirm what you want to hear.
When I come across these rumors and stuff, I want to know if its true, not if it says something I want to hear.
These rumors an alleged scoops have a bit more weight to me given:
* the announced castings of Foxx and Cumberbatch,
* given Wandavision and Doctor Strange 2's relation to SM3,
*given the new deal between Sony and Marvel in which Feige alluded to Spiderman crossing universes,
*given Mysterio's mention of the multiverse and Jk Simmons appearance as Jameson ,
*given that Sony allegedly wanted Garfield and Maguire to provide their voices for Into The Spiderverse film ,
*and especially given Sony's carefully worded , " It's not confirmed", statement.
Now, a team up may not happen in SM3, though given the available evidence , the idea of the multiverse not being touched on in some form is unlikely imo .
It could be that SM3 only sets the stage for a Spiderverse film down the line . Or it could be they announce the cast of SM3 and it turns out that Electro is the only villain and it won't deal with the multiverse at all. There are lots of possible outcomes.
Either way though, I have faith that Feige and co are going to give us a good Spiderman 3 , whether that's a multiverse film, or a film with a much smaller scope like the first two.
So if it happens, great. If it doesn't happen , I'll still be looking forward to what Feige has to offer.