Hello,
if I understand correctly (google translation), then you want the following:
Start a new character.
But keep everything what the high level caracter has.
This is possible via the admin menu. There you can set the level of the character. You can set Level 1. Then you die. Now start from scratch and have everything you had.
Personally, I would like to have the following. There are at least 3 scores, as with most singleplayer games. I want to start a new game. I want to keep my old score. I do not want to set up an extra account.
Best regards