I think it'll be 2021. This year I think will sell a little bit more than last year, maybe 29 million.
Next year, with Pokemon Legends, BotW2, Splatoon 3, and who knows what else, I don't think Switch will lose much steam, it very likely could do another 25+ million year next year, but I suspect it won't quite be able to match 2020 and 2021 numbers. Now if they throw out a price cut and like a new 2D Mario game to really pack the year with mega sellers then all bets are off. So I won't put it totally out of the question that 2022 could be the peak, but I think it'd only happen if Nintendo got really aggressive with trying to push sales by actually doing things, which isn't really their style.