"Spider-Men" is an unmarked sequel to Spider-Man: Shattered DimensionsOn the one hand its a spiritual successor, since both stories involve multiple versions of Spider-Man teaming up. And on the other hand, it's a literal sequel. Over the course of "Dimensions", Mysterio was putting together data on the Tablet, getting a lot of irreplicable data on dimensional physics. Using this, he went on to become Ultimate Mysterio, setting up the entire plot.
Peter's final piece of advice to Miles before being cut off would have been about 'power and responsibility'.