I don't think not being relatable to urban audiences is the issue.
I actually think Brandy trying to pigeon hole herself into urban spaces has actually stifled her career to a certain extent. Even if these spaces and publications are praising her NOW. They haven't always. Those spaces tend to be misogynistic and have preference for men and rappers. The R&B Female artists get some consistency, but it's not outstanding. Brandy's album sales are pretty much on par with her peers without having to put in as much effort when it comes to branding and marketing.
Brandy just hasn't tapped into her true audience enough. The Disney girls, the 90s Y2K girls, soul-pop crowd, international markets. I think Brandy should actually step outside of R&B and go into Adult Contemporary. Brandy has crossover appeal, which some/most of her other R&B peers don't. And she can hit up international markets easily with her voice and catalogue of music.
She has a regal, earthy, wholesomeness to her and that is refreshing for a Black artist even if urban audiences don't appreciate it.