Limits were meant to be broken.
Twilight Princess was the best selling Zelda game and it didn't even reach 10 million. Breath of the Wild is on track for over 30 million.
Not a single Fire Emblem sold over 1 million before Awakening. Not Fates and Three Houses have each sold at least 3 million
To my knowledge, the best selling "Metroidvania" is Hollow Knight, which was at 2.8 million sales by February 2019. It's more than likely sold well beyond that since then. So the ceiling for "Metroidvania" is even higher than Metroid itself.
So, Dread could absolutely do the same thing as the other Nintendo games I've mentioned. The Switch does not give a shit genres or limits. It just sells. Along with everything on it. Dread has all it needs to break that glass ceiling wide open.
If Dread even gets close to Hollow Knight it will be far more impressive since it's only available on one device, whereas Hollow Knight is available on many.