Not a Japanese so don't count me on this, but I think Yume is a girl's name. So between the two, Aito is more fitting.
And as far as I'm informed, Japanese parents have deep and serious thoughts in naming their children—actually on the meaning of the Kanji/s used. So with respect to that culture, I hope you could firstly provide "who" the character is (personality, traits, life, journey, ambitions) to find a fitting name.
Aito in itself has different meanings depending on the Kanji used: https://japanese-names.info/first-name/aito/
With that being said, maybe it will be more actually helpful for you to browse names by searching "Japanese baby boy names with meaning," select your favorite ones, and ask a more Japanese-oriented audience to help you gain more definitive insights on the Kanji.