I think this is how it will break out.
Alito, Thomas and Barret will vote to overturn.
Jackson, Sotomoyor and Kagan will vote to uphold.
The real question marks are Gorsuch, Kavanaugh and Roberts. They've all shown signs of being actual jurists from time to time.
On the legal question, there's really no doubt. Trump formented an insurrection. He did this openly on Twitter and national TV. We all saw him do it.
The problem of Trump is that he's always been a person who is manifestly unfit for the presidency, but since 1974, respect for the Presidency as an office has declined so much that it doesn't matter to people.