Step1: Start a new game and watch the cutscene.
Step 2: Go to the menue and change the game language to Japanese.
Step3: Quit the game.
Step 4: Navigate to the Savegame location folder. For XBOX GamePass for PC it is here: C:\Users\YOURUSERNAME\AppData\Local\Packages\PlayfulCorp.49013BFBD8849_7n7np5b8s1z70\SystemAppData\wgs
For Epic users the file is here: C:\Users\YOURUSERNAME\AppData\LocalLow\Playful Studios\New Super Lucky's Tale\Save
For Steam users the files can be found here: C:\Program Files (x86)\Steam\steamapps\common\New Super Luckys Tale\nslt_Data\SavesDir\76561198125240469
Epic and Steam users will only have to handle 1 file and not a folder and a file like Gamepass users.
Step 5 (for Gamepass): Enter the numbered folder and copy both the folder and the container index to a safe location. https://imgur.com/GwJd1uo
Step 5 (for Epic and Steam): Enter the SaveDir or Save folder and copy your file to a safe location.
Now everytime you want to restart your run, all you have to do is delete the files inside the numbered folder and replace them with your saved ones