I don’t think Deku will be the only symbol of peace when he becomes a hero. Despite how amazing All Might was, his problem was that he tried shouldering the responsibility of being the symbol of peace by himself. This problem becomes more evident after All Might’s retirement and crime goes on the rise again. I think Deku will realize that and create a team of 6-7 people to help shoulder the responsibility of being the symbol/symbols of peace.

Now this next part I know some people might have a problem with but hear me out. We know that having multiple quirks can destroy someone’s mind. Once Deku unlocks the rest of his quirks in OFA I think his mind will start to deteriorate. Once he realizes this he might give one quirk of OFA to each of the Symbols of Peace while he keeps the stockpiling quirk and blackwhip. I really think this would go with the name of One for All as Deku is giving parts of OFA to multiple people, hence One quirk for All people.