I'm not taking some hard position in favor of either of you guys' take on this but... I will say that while your take can ring true in one sense, I can easily see that flipped on its head too where an actor could (and some certainly have) sacrificed having a bigger career for the sake of their personal joy or working on their craft as well [just in a less popular or mainstream sense]
For those guys (who came out) I think their love of the craft just manifested in a different way. I guess it's all a matter of perspective and individual priorities.
Not to be rude, but Richard doesn't really have a bigger acting career. I kind of feel like his chances of becoming an A-list actor are dwindling. Younger actors like Timothee Chalamet, Austin Butler, Paul Mescal, etc. have kind of taken over that lane.
It could still happen, but not from being on a show like Citadel. He would need a star-making turn like being James Bond or something. I know he auditioned for Gladiator and didn't get the role. That would have been huge for him as well.
If he did come out as bisexual, I don't see him suffering any from that. He'd still have the same type of mid-level career he has now. I don't think he's gained anything from staying quiet about it.
He doesn't need to say anything of course. It's no one's business.
P.S. - I actually think he's way hotter than the three guys I mentioned above. He just hasn't broken through like they have.