I don’t think it’s gonna happen. They’d surely have released news this big along with the recent cast announcement.

Lucasfilm clearly stated that this is the “final installment of the Skywalker saga”. Singular, not plural. I don’t think they’re all of a sudden going to change this into a two-film ordeal partway through development, especially after the bad rep they’ve acquired after the productions of Rogue One and Solo. They’re gonna take this as smooth as possible and strive towards making a coherent, satisfying conclusion.

Just my two cents.