Found an old but still curious site to view population density and estimate population within a circle/polygon. Based on 2015 estimates, but with more granularity than Census tracts:
https://sedac.ciesin.columbia.edu/mapping/popest/pes-v3/
Population density dips around the north Beltline, likely due both to the high concentration of commercial uses and the absurdly low, exclusionarily zoned densities there (soon to change). What other areas stand out?