If the appeal is "oh I always thought I was a beta... what is this feeling?? i want to have a dick inside me!!", ain't that the plot of Love Shuttle? Except he always knew he was an omega but his pheromones started acting late. Same concept but Love Shuttle's execution is better than 'beta turned omega because of bite/drug/whatever'.
I recommend Kashikomarimashita Destiny. Great alpha/beta couple that goes beyond the usual fated alpha/omega pair. Love is An Illusion also has an alpha/beta side couple. I never cared much about the main pairing (same concept only it's an 'alpha' thinking it's an alpha but turned out to be an omega). And there's a chinese web novel called '前任都是alpha[ABO]' that revolves around a beta dating alphas who would usually throw him away after meeting their 'fated pair'.

I just hope there isn't any drama that could hurt the two.. ;w;
Like Matsu struggling to avoid maybe a rude omega, who's jealous. Or a twist that Yuuki is actually an defective? omega, like something medically up that suppresses alot of it. Cause I actually had a dream about that as a twist.
Cause didn't they say in omegaverse that it's nearly impossible to gain more muscle?
I just hope he has a high a'f metabolism. xD
Anywho I'm done rambling.