Alright, let's see... Since Nintendo struggles with shortages and this year won't meet my expectations, I go with these numbers:
2022: 123m (+20m)
2023: 137m (+14m)
2024: 144m (+7m)
2025: 147m (+3m)
2026 - end of life: 150m (+3m)
So I expect that Switch will end up below PS2 and DS, but at a pretty close gap. Very difficult to me if Switch reaches 150m or not. It would have been much easier without chip shortages...
Next year should be (besides shortages) pretty safe another 20m+ year with the new OLED model and the already very strong first party software support. In 2023 I expect only Metroid Prime 4 as the last big first party title for Switch. The Switch successor should launch holidays '23 or March '24 with the all-new big open world 3D Mario and Mario Kart 9 within its first year.
My favorite Switch release is Zelda BotW, besides Octopath Traveler and Dragon Quest XI.