I think 2021 will be the peak year. However, I cannot rule out 2022, considering the potential for Splatoon 3, Project Triangle Strategy, Mario + Rabbids: Sparks of Hope, Pokemon Legends Arceus, and, possibly, BotW 2. Not to mention Nintendo hasn't really talked about 2022 games anyway so there are bound to be surprises like what we saw at E3 2021, with Advance Wars 1+2 Reboot Camp, Metriod Dread, Wario Ware Get It Together!, etc. 2020 was a unique year (pandemic and Animal Crossing New Horizons exploding onto the scene) that will likely not be matched again, nor expected to. Nintendo was able to do what it needed to do this year, maintain momentum from last year's crazy, unpredictable, but incredible blowout. With the world still not out of the woods yet with COVID-19 and developers still trying to play catch up with their development schedules, Nintendo was able to provide a plethora of unique content that can satisfy a variety of consumers for Switch owners and potential Switch owners.
Of course, things could change and we may have developments that we may have never expected (like Ring Fit Adventure being as popular as it is for a game that pretty came out of nowhere with little time between initial reveal and release). Who knows how this new Switch OLED will do in the market and how it will be received by consumers. It will be interesting to say the least.