There's no trades to report a format to anymore. Outside of what a station tells Nielsen (which is not always reported correctly) or when Mediabase classifies a station for reporting status, the only other place that really spends any time classifying a station is RadioInsight as we do not rely on the classifications of others but use them for guidelines.
I'm not sure where you see that much of a blurring between the two outside of a couple stations that blur the line between the two like WVEE Atlanta as noted below.
Since I stopped using the "Urban" terminology in 2020 for its coded racism, the classifications we use for the most part are :
Hip Hop - Station mostly playing current/recurrent Hip Hop. KBFB clearly in that mode. But different from Rhythmic CHR, which usually targets a broader white or Hispanic leaning audience too. WQHT New York is Rhythmic CHR. WWPR New York is Hip Hop.
Hip Hop/R&B - Station such as WVEE Atlanta that skews slightly older (more or less a Hot AC) with mix of both genres
Adult R&B - The former Urban AC such as KZMJ/KRNB Dallas.
R&B Oldies - Self explanatory such as WDIA Memphis
Classic Hip Hop - Gold based station (Differs from some that are Rhythmic AC/Rhythmic Hot AC that also have pop records or recurrents and target a more mass-appeal demo). As an example WBMX Chicago is Classic Hip Hop, but sister KHTP Seattle is Rhythmic Hot AC