https://www.webtoons.com/en/challenge/prince-akihiko/list?title_no=769334
A web manga about prince Akihiko's journey with his sword princess and gf, princess Aeleemoona to become a respected prince and great classical pianist in futuristic Aippon (Neo-Nippon) empire at 27th century. He wants to achieve all of that, meanwhile at the same time, the empire and world threatened from other unimaginable dark force empires that causing historical disruption, reality disruption, inter-dimensional chaos even the planet got isekaid into many generic medieval isekai worlds...What?