If Bruce and Assistant Reader was in the omegaverse, I'd make Reader a scentless (a regular human (NOT a Beta)) that lives with an omega roommate.
Id do this because I think it would be funny for omega Bruce to accidently mistake your roommates scent on you as your own and assuming you are also an omega.
The thought of omega Bruce confiding in you his struggles as an omega thinking you can relate is so funny. I mean, its not like you don't understand his struggles, you've had to shoo a couple alphas and betas away from your shared apartment as a favor to your roommate.
However, that understanding just makes Bruce believe more strongly that you are an omega with either a weak scent or very strong scent suppressants.
And as he starts to become obsessed with you, he starts developing this delusional fantasy where two omegas find comfort in each other.
What can he say? He's a sucker or Omega x Omega stories.
Unfortunately for you, because of this misunderstanding, your already needy boss gives you more tasks to handle as his assistant. You have to keep a bottle of heat suppressants on you at all times, if he is in heat, you have to pick up supplies that he needs and guard him from creeps that want to take advantage of him in his current state.
And if that wasn't bad enough, after you finally get him back to his manor and help his butler get the large and needy omega in bed, he won't let you leave.
He will wrap his arms around you and pull you close to him, burying his face into the back of your shirt as he breathes in your faint, but comforting scent.
"Stay... stay with me, please... please don't leave me.." the man mumbles as he uses his body weight to keep you in his bed, moving his face from the back of your shirt to the nape of your neck, taking in every minute smell you carry and produce.
Scents that he plans to incorporate into every inch of his manor.