Thomas A. answered 07/28/19
Ivy League Grad & Published Author with 10+ yrs of Teaching Experience
While I would have liked to see how you propose to use this in a sentence (for context), it is clear that your proposed phrase of "one is all only" is awkward at best and would likely be confusing to most readers in the English language.
But if you are a non-native speaker, please know that virtually any concept can be conveyed multiple ways when writing in English.
Good luck, and please feel free to follow-up with additional questions!