Responses
https://www.mangago.me/read-manga/longing_and_lies/
Similar music background although different instrument. Less about rivalry and more about working together though.
Little spoiler:
The mc kneeled for the ml to let him 'see' his heart
a story where the mc and ml have dynamics like jeongyo(ml) and pi-o(mc) from Four Hands Two Sonatas
(similar builds too but its okay)