Spider-Man: Far From Home - What The Title Means
1. Venom?
Now, this is the most out-there theory of the lot, but it might just have something to it.
When Homecoming's title was announced, it was very quickly noticed by fans that the title had been borrowed from an apparently obscure (relatively so anyway) comic from the aftermath of the Secret Wars crossover event. The comic saw Peter's return from Battleworld, where he'd come into contact with the symbiote for the first time and saw the debut of the iconic black suit.
Obviously, that didn't happen in Homecoming, but there's something even more pertinent in the Far From Home title that could again refer to Venom/the symbiote. Putting together the points previously about Peter struggling to come to terms with the aftermath of the Infinity Saga, losing something of himself and possibly ending up in an entirely different universe, the stage is set for that same symbiote encounter.
And surely Sony would take any opportunity they could to link the MCU to their own Spiderverse for the purposes of longevity after the big deal runs out (assuming it's going to)? Who is to say the symbiote would have to be the same one that we will see in Venom? The symbiotes are an entire alien species, after all, so that's easily covered.
Could it be that the MCU's Spider-Man trilogy could end up being a means to set up a meeting between Tom Holland's Spider-Man and Venom back with Sony after all?