There are eighteen citations of Matthew xxviii. 19, and always in the following form: “Go ye and make disciples of all the nations in my name, teaching them to observe all things, whatsoever I commanded you.”
Even if that is the case it doesn't change what it means there in saying 'in my name' or 'in the name of'. Saying that does not mean disciples take on to themselves the name "Jehoshua'. It means that they would be going making/teaching with the authority of Jehoshua behind them to go and do that disciple making work.
The only name said to be given to use/apply to disciples is 'Christians'.
[ 18 Jesus approached and spoke to them, saying: “All authority has been given me in heaven and on the earth. 19 Go, therefore, and make disciples of people of all the nations, baptizing them in the name of the Father and of the Son and of the holy spirit, 20 teaching them to observe all the things I have commanded you. And look! I am with you all the days until the conclusion of the system of things.”]
[ 38 Peter said to them: “Repent, and let each one of you be baptized in the name of Jesus Christ for forgiveness of your sins, and you will receive the free gift of the holy spirit.]