What about a Spider-Verse crossover that is sort of based on the new movie? One that has Miguel O'Hara turning 2099 into a base for a new Multiversal Web Warriors strike force made up of Mayday, Annie, Spinneret, RYV Peter, Peni, Ham, Noir, Miles, Gwen, Hobie and Pav? And have The Spot be their first big bad!
"The Enigma Force is not a tool to be manipulated by mortals. The Enigma Force comes to those it deems worthy. What temerity, what arrogance, makes you think you are worthy? Have you not all made mistakes? Unforgiveable ones?" - Captain Universe
"Call me an Avenging Angel, Baron, come to safeguard Earth...call me CAPTAIN UNIVERSE!" - Ray Coffin
"You're my heart, Mary Jane Watson...you're my jackpot." - Peter Parker
End it at 3 and then have Miles appear in other stories, but allow the concept to be gone for a little so that people miss it and then you can bring it back later.
If they make this basically a perfect trilogy they've earned letting it sit for a little while.
If they ever did a 4th one, it shouldn't have to do with the Spider-Verse but instead be a grounded story about a singular character and their heroes journey to becoming Spider-Man. But one that feels different like how Miles' did.
So I'd recommend a Mayday movie showing her as a teenager and becoming Spider-Man and how she deals with both her parents being who they are. Sounds like a good idea to me.
Standalone movies would probably work best. A Gwen movie, a Mayday movie, a Spider-Man Noir movie. Things like that.