Sorry but I can't reproduce your issue or I don't understand it, can you explain to what "whitespace" you are referring to?
library(tidyverse)
df <- data.frame(
"category"=c("A", "B", "C"),
"color"=c("#98D278","#ea4f62","#f5a623"),
"volume"=c(4321, 1200, 500)
)
ggplot(df, aes(fill=category, x = 2, y = volume))+
geom_bar(stat = "identity", alpha=0.8, fill = df$color) +
xlim(.2,2.5) +
coord_polar(theta="y") +
theme_void() +
theme(panel.background = element_rect(fill = '#1b2036'))
Created on 2020-04-20 by the reprex package (v0.3.0.9001)