Placing scale bar off map, with legend (ggspatial)

General
1

How could I go about placing a map scale bar (currently made with ggspatial's annotation_scale()) outside of the map area, and with the legend.

Here is ggspatial's reprex for the function, with color added in so we have a legend:

cities <- data.frame(
  x = c(-63.58595, 116.41214),
  y = c(44.64862, 40.19063),
  city = c("Halifax", "Beijing")
)

ggplot(cities) +
  geom_spatial_point(aes(x, y), crs = 4326) +
  annotation_scale() +
  coord_sf(crs = 3995)cities <- data.frame(
  x = c(-63.58595, 116.41214),
  y = c(44.64862, 40.19063),
  city = c("Halifax", "Beijing")
)

ggplot(cities) +
  geom_spatial_point(aes(x, y, color = x), crs = 4326) +
  annotation_scale() +
  coord_sf(crs = 3995)

I've looked into using cowplot with its get_plot_component(), but the scale bar isn't one of the components.