its a point of origin paradox violation, you cannot go back in time and kill ur self before u left, if u were to attempt to do so the universe as a whole would most likely play a trick on ur vortex or teleport or whatever and divert u to another time frame, you would get back just intime to find out u had went into…

1) How would you define a branch? As to how to navigate between them without changing history back to the previous version/If the universe did copy itself without it just overwrite the previous copy instead of splitting into two pristine copies?