You have to wait for the Nintendo Retro Postal service to go live in April 2020.
There you can order all your favorite games from Nintendos long history for only $29.99*
After 2-4 weeks of delivery time you will get your order that contains a code to download the game on your Nintendo Switch.
After first activation you can play the game for up to 10h of playtime or 2 weeks of real time.
So you will never get bored with old games and can try out the whole libary. The game will even uninstall by itself.
*Only one active purchase per Nintendo Account allowed.