the leaderboards already have a category wherein you load a chapter and just play straight through levels 1 through 20. you can find the category for each world by clicking level leaderboard, selecting the chapter, and then selecting "individual world" from the list.

however, it seems like race mode on the switch is rather different from that. this puts us in a bind, since nobody on the mod team actually has a switch, so we're hearing about race mode second-hand.. can you detail the glitch you found?