Like the comics story arc written by Bendis, the rival mob boss could be Hammerhead or replaced with a newer character like Mr. Negative. Maybe he has ties to the Ten Rings to further justify Shang-Chi’s involvement? Kingpin could even give Spider-Man intel to go after this rival, like he does in the comics (“go be the hero”), while the two eat pizza at Fisk Tower (the previous Avengers tower).
Kingpin uses his Enforcers to fight his battles, comprised of Mac Gargan, Fancy Dan, & Ox. Gargan dons a Scorpion mech-suit, and similarly Fancy Dan & Ox get MCU-tech upgrades (opportunity for the Tinkerer to return, and Melvin Potter from the Netflix series). Kingpin is still a menacing character, but he operates inside the MCU now so things around him are more colorful.
Peter is especially tested when he bonds with the alien symbiote after it’s accidentally released during a fight inside Mr. Negative’s research facility—maybe the symbiote also serves as the origin of Negative’s Lightforce/ Darkforce powers?
Since the Enforcers are the first super villains Peter is facing after downgrading to a cloth suit following the events of
No Way Home, he finds himself overwhelmed and so the alien costume is a welcome help. The symbiote preys on Peter’s loneliness which he struggles to overcome. When he does eventually separate himself from it, he buries the symbiote under cement at a construction site (for a rainy day or, more specifically, a sequel).
MJ (Zendaya) appears in a minor role throughout the film. Peter frequents the coffee shop where MJ works again now that she’s back home for summer vacation. The two have developed a friendly relationship, as regular customer & friendly barista. No romance…yet. And she has no idea about Spider-Man or their past together.