Forza in Early 2022 would be fine since Forza 7 and Horizon 4 are already on Game Pass. Those will be two racing games to play for those buying a Series X|S.
My thinking is Forza 8 in either late 2021 or early 2022 and then Horizon 5 in 2023. I think that comes out after Fable, which I'm putting down for late 2022.
Oh damn! Welcome back. Have you on Xbox and you always top of my leaderboard. I still hope Horizon comes out earlier. But I agree with the other two. Hope you stick around, Ryuu's done a great job with the thread.