It would not be unrealistic that a CA at a no-beard airline (especially one with more draconian uniform policies) might be concerned about how that would look to the pax. Yes, some airlines specify "clean shave" as a JS requirement... that was intended for guys coming home from vacation but technically would apply to any beard. I'd guess you'd be fine 9 out of 10 times, but if it were me I'd probably JS in uniform... making it clear that your company allows beards and you're not just trying to push any boundaries.

Or better yet, just mask the eff up, and tell them "just so you guys know, I'm vaccinated" That should be good for years to come.