Pritchard is probably good enough to start this season for BOS, depending on how Simons works out, but I think he is most valuable to the team moving forward coming off the bench. So if Pritchard is going to be a bench guy when Tatum comes back for 2026-27 and beyond, then the best thing is to use him in that role for 2025-26, at least as things stand now. There is no reason not to start Simons (I can't see a scenario where they both start).
If we trade Simons other the roster changes otherwise, I have no qualms at all having Pritchard as a starter, none.
I know that who starts doesn't mean who finishes, but the question posed by this thread is Who Will Start Game 1. A thread based on the question of who are the best 5 to close games, could result in different answers.