I'm pretty sure it's an alpha X alpha romance! :)
That's a standard Japan came up with. Korean Omegaverse has often shown that Alphas can be bumbling fools while Omegas are domineering CEOs. Unromantic is a good reference.
Siwoo and Byul are both alphas. Byul is handsome, not academically smart but I think he got his father's music talent.
I think it said siwoo was an alpha
No. Author already confirmed in X. It is an alpha X alpha story, and Siwoo is the active.
This is just my hot take, but we already know Byul is a dominant alpha as stated from the previous story.
However, people need to realize that "not all alphas are academically or physically gifted". It's ridiculous to assume that alphas have to be "handsome, smart, athletic, etc."
But back to Byul already being established as a DOMINANT ALPHA, I'm sure Siwoo is either a beta or he's a recessive omega who hasn't manifested yet.