ENDGAME SPOILERS
It seems the thematic thrust of this film is going to be what Peter does now that Tony Stark is dead: Will he step up and become the "next Iron Man", giving the world the hero it needs. I guess this is why they had Peter leaving New York for an adventure across Europe. It seems Peter is reluctant to go beyond being the "friendly neighbourhood" hero, and perhaps will be looking up to Quentin Beck as the father figure to replace Tony.
They're apparently talking about the multiverse in this one. Beck is said to be from an alternate earth, come through a tear in reality that happened because of "the snap". This would be a pretty convenient way to start to fold some of Disney's new properties into a "Marvel multiverse". The final film of Phase 2, Ant-Man, introduced the Quantum Realm, which was essential to the ending of Phase 3. Far From Home is the final film of Phase 3 and is introducing multiple alternate realities.
Buuuuuuut (and here I will spoiler, because I'm going to be using comics knowledge to predict the film's plot):
Spoiler
Mysterio is a damn liar and a fraud. His whole thing is illusions and fakery, sometimes using it to try and pretend to be a hero, to make himself look good. It doesn't take much thought to realise the thematic and plot elements of this story add up to one thing: Peter thinks Mysterio can be the mentor he wants, then he finds out Mysterio is a fake and has to step up himself.
The question then would be: is Beck lying about being from an alternate reality, or just about being a hero? Maybe the entire multiverse thing is a fakeout.
The question then would be: is Beck lying about being from an alternate reality, or just about being a hero? Maybe the entire multiverse thing is a fakeout.