I was planning on trying to speedrun this game on Nintendo Switch (Mainly because it's the only version I have, and I don't plan on buying PC version anytime soon) and I realized that I can't exactly True Reset unless I complete a True Pacifist Route. Or am I missing something?

Thanks

The in-game True Reset function doesn't actually delete the save data so starting a run with a True Reset would not be a valid run. You'll need to delete the game data in Data Management. We refer to it as 0-reset to distinguish it from the True Reset option. Here's a guide for deleting save data on various versions: https://pastebin.com/EixYz5hk