Venom 3 has a villain problem now that it's been established that the Sony Spider-Man Universe is a distinctly different universe from the MCU, but Spider-Man: Across the Spider-Verse can help to fix this issue. Despite the critical failure and commercial underperformance of Morbius, Sony is pushing ahead with their Spider-Man Universe, and Venom 3 has now been formally announced. While Sony's villain movies are connected to the MCU multiverse, reusing a villain from previous Spider-Man/MCU movies could easily undermine and detract from Sony's universe-building.
One of the problems 2018's Venom and the 2021 sequel Venom: Let There Be Carnage had was that the villains were essentially just twisted variations of Venom. Broadly speaking, there is little distinction between the symbiotes, especially in the action scenes, and having Venom go up against yet another symbiote in Venom 3 would likely feel repetitive and uninspired. Over the last two decades, Sony had worked its way through the A-list of Spider-Man's rogue's gallery. While there are still 60 years of comic history to draw from, Spider-Man's main villains such as Green Goblin, Kingpin, Doctor Octopus, and of course Venom himself are the ones that remain interesting in terms of character and abilities. Spider-Man: Into the Spider-Verse and Spider-Man: No Way Home both used this to their advantage in telling a multiverse story with classic villains in different ways. However, to fix its villain problem, Venom 3 needs to forge closer ties to Spider-Verse 2 than the MCU.
While Spider-Man: No Way Home successfully tapped into fan nostalgia for the classic villains seen in earlier movies, it would be unwise for Venom 3 to use these classic villains yet again (either the same actor or recast) as its own antagonist. It would be likely to be confusing to general audiences familiar with the Spider-Man movies and invite unflattering comparisons with Marvel's more successful cinematic universe. Spider-Man: Into the Spider-Verse meanwhile brought to life distinctively different universes, and Spider-Verse 2 can set up a plethora of visually different villains that Venom 3 could use. Tapping into the noir universe or the anthropomorphic universe for example would be a great way in live-action to bring across a villain to Venom 3 that is fresh and interesting for the audience. With this in mind, Spider-Verse 2 could end with some villains staying stuck in Venom's universe, ready for the symbiote to go up against in Venom 3.
Now that traveling across the multiverse is becoming more common, there is greater scope for Venom 3 to be visually and narratively different from the earlier Venom movies—and just as boundary-pushing as the Spider-Verse 2 is shaping up to be. It would also avoid the problem of repeating the same Spider-Man villains in the Venom movies and wouldn't be limited in who it can show without complications or comparisons. Adopting different visual styles, such as anime or black-and-white noir, is easier to pull off in the context of animation. Notwithstanding this, given the visual effects-heavy nature of the Venom movies, contrasting styles could still work in live-action and help Venom 3 positively stand out from both the previous Venom movies and other live-action Spider-Man/MCU movies.
Outside of the MCU Spider-Man movies, Sony's Spider-Man Universe hasn't enjoyed the same level of success as the MCU. Trying to ride on the MCU's coattails through limited association, familiar faces, and shoehorned multiverse cameos (such as Michael Keaton's uninspired Vulture appearance in Morbius) isn't a good creative decision or business decision long term. Having Venom 3 lean more towards Spider-Man: Across the Spider-Verse rather than the MCU could work more to its advantage and fix Venom’s villain problem.
