I would have been more than willing to bet he would have gotten the third movie of his trilogy in Phase 5. Doubt they would wait that long between movies.
If he stays in the MCU, it would be interesting when they'd be able to get it film out. The Marvel release calendar is pretty crowded right now.
They have the next two years locked down. I think beyond that, the next likeliest projects to get released are GOTG3 and Black Panther 2. There's also franchises like Captain Marvel and Antman which Matvel is trying to get out and are safe money makers for them.
And then there's new projects and characters on the horizon, including Blade or whatever they're planning with the Fox properties.
Unless Marvel bumps up their output to 4 films a year, you can easily see a scenario where a MCU Spiderman film could only come in 2024 or later, even without this fighting in the background.
Edit: The more I think about the scheduling, I'm wondering if this is one's if the negotiation issues. Sony would want a Spiderman film in development right away as it's their biggest franchise. For Marvel, it's a much smaller priority that can be pushed off a few years.