I want the third Spidey Movie to have the Sinister Six...

We have Vulture. Now Mysterio is coming. All we are missing is Kraven the Hunter to have a Cinematic version of the Sinister Six... but, I know, 3 out of 6 aren't part of the MCU...
How can we fix this?
Oscorp... and this is How I'd do it:
We KNOW the invasion attempt of NY by the Chitauri in Avengers and Vulture's  tech was reverse-engineered by the Tinkerer.
What if Norman Osborn has gotten his hands on Chitauri tech and other things that were obtained illegally and are being experimented on as part of Oscorp's Black Projects.
That gives us a spot for Otto Octavius: an Oscorp Scientist experimenting with Chitauri tech.
Among the illegally obtained items, we could have two humans prisoners whose bodies were altered by Chitauri tech:
Maxwell Dillon, an Electrical Engineer, whose body was turned into a living Electrical capacitor, after the NY Incident.

Flint Marko: a carreer criminal who was hiding at an Oscorp Testing Facility, where a bomb using Chitauri tech was being tested. The incident fused Marko with the sand frim the site, making him into a man made out of living sand.

The security for Octavius's site is a Russian PMC, led by a man called Sergei Kravinoff; a man with heightened senses and an unnatural ability to track aninals or people alike. The source of his abilities is that the Kravinoff Estate was able to breed a weaker strain of the Wakandan Heart Shaped herb. Sergei uses a synthesized version of the herb which temporarily grants him the powers of the Black Panther.

We get the accident that fises Ock to his arms. (Most likely sabotage from Norman after discovering that Otto was trying to cure Dillon and Marko instead of weaponizing them) Norman fires Kraven and Octavius. Both desire revenge and they team up. They convince Marko and Dillon to join. Kravinoff blackmails Adrian Toomes into joining via the Chameleon. Mysterio joins because of reasons. Spidey is forced to face the Six as they set up an attack on Oscorp.

We could end uo with Spudey beating Ock and getting knocked out by Norman, who in desperation due to the attack used an experimental take on the Super Soldier serum...

I know it feels bordeline DC to have Sandman and Electro kinda established there and "rushing them", but we don't NEED to sit trhough another origin for them, since we didn't have to sit through a third Spidey Origin. Here Otto, despite being "The villain" he has altruistic motivations. He TRULY believes that he is doing this to cure Dillon and Marko. The "real villain" is Kraven, who is doing his part for greed and revenge. Thanks to Chameleon, he knows about Norman's experimental Super Soldier Serum, which Kraven wants to combine with his Strain of Heart Shaped Herb to become even stronger. Kraven is the one who brought Mysterio and Vulture into the fold. (Still not sure on what would motivate Mysterio, but Blackmail and threats towards Liz can work on Toomes)

I kinda wish we had "more time" but with SONY working hard on screwing up everything Spidey... Black and Sable, Morbius, etc. I'M LOOKING AT YOU!  I'm afraid that if we don't force the Six soon, Sony will want to make a Spider-Man-less Sinister Six movie.