It looks like the Switch OG alone will reach 20 million units next week.
Speaking of which, I have an interesting idea to guess the final hardware sales of each SKU of the Switch.
For the Switch OG, I seriously doubt it will ever reach 21m. So let's say 20m. For the Lite, I think 7m is doable, 8m seems too difficult. As for the OLED, I would say, 10m is guaranteed. But a higher number, I can't say, should still be possible, depending on when the next generation is launched and whether the OLED will be discontinued at that time.
In this case, it means that the final sales of the Switch in Japan should be at least 20+7+10=37m.