My Archrival Turned into a Sweet Omega

Huo Shiyu, the legitimate daughter of the Duke of Rong's household, grew up in military camps and was like a man.

The Old Madam worried: With her daughter like this, how would she ever find a good husband?

But...

The Old Madam no longer needs to worry. Huo Shiyu has become a real man!

No, she should be called a female alpha with a big dick.

ABO setting, female A and male O

The heroine is a tough, tender-hearted woman (?) and the hero is a scheming little white flower.