I believe the OLED was actually going to be the Switch 2 (or Pro), but the pandemic made them change plans.
The chip market went bananas, and it was impossible to produce some chips at volume and at competitive prices.
They probably decided to wait a bit, and evaluate alternatives and probably dedicate more time to R&D.
Whatever they do, as long as it is compatible with the Switch, I’ll be happy. It’s one of the best game libraries they’ve had in a long time.