I think a Pro model will release in 2021. But it'll just be a different version of the same system, like the Lite. It isn't gonna run different games, that would be stupid. It'll just run the current games with better resolution or better fps. I could totally see them dropping the Lite and OG Switch to like $180 and $240 or something and then coming out with the Pro at $300 so they maintain that higher price point for people who are willing to pay a premium to get the best version (and because there are always a certain amount of nintendo fans who will double dip on the same system to get the different versions).
The's no point for that the Lite was not just to be a cheaper version it was to open the Switch up to something handhelds have had over consoles for decades and that's being more than one per household this is why a portable only version was made as more than one person in the house can be on a Switch which is especially important for families with kids or households with more than one person who games in general.
A pro version in 2021 offers no such benefits it does not open any new strategy for Nintendo nor are the people who pay premium prices the people Nintendo were aiming for to begin with that crowd wouldn't be interested in a Switch Pro if they don't already have one as the platform was never about what they're looking for.