When you start Mario Kart Tour for the first time, you are given two starting characters for your roster randomly, that is different for everyone playing the game.
Sometimes you won’t get the character you wanted and will be forced to invest real money into the game to get the one you did want. If you are starting the game for the first time, however, and want to get a better character that is more your playstyle, you can always delete your save data and start again.
Doing so will force you to redo the tutorial multiple times over until you do finally get the character you want but, hey, it saves investing actual money hoping RNG is on your side, right?
To restart the game, load up the settings option in the bottom right of the screen and scroll down until you see an option called “Start Fresh.”
Pick this option and go through all the steps to delete your save file, and it will unlink your current Nintendo account and all the data associated with it. You then need to close the game and reopen it, and you should be given the option to relink the same account albeit with none of the data on it.
Then do the tutorial again and again until you finally get the character(s) you want and start enjoying the game.