I wonder if Switch could still finish at ~32m by the end of the year. In 2019, Switch did 4.49m with Pokemon Sw/Sh, Luigi 3, Mario Maker 2 and Ring Fit among its biggest titles.
Fire Emblem: Engage, 2D Kirby, Octopath Traveller 2, Bayonetta Origins and possibly Advance Wars reboot. A Mario game that ties into the movie is also still a possibility. Could be some 2/2.5D platformer, 3D platformer or maybe even an adventure game or rpg.
Another 4 million this year is definitely doable. I'm also not convinced Nintendo is done revising the Switch. I think we'll see another version of the console release this year with a new Nintendo releasing in early 2025.