Is there a way to have a raster gradient through NA spaces? Aiming to mimic raster output from ArcGIS GWR

Question

I'm trying to mimic the raster style output you get from ArcGIS Geographically Weighted Regression, where instead of simply plotting the coefficient/value in the raster cell that aligns with the coordinate point assigned the value leaving all in-between cells NA, it (at least appears to) fill them by a gradient. See ArcGIS screenshot for what I am aiming for. Thanks!

Here's an repex

library(tidyverse)
library(sf)
library(stars)

df <- quakes %>%
  select(depth, long, lat) %>%
  st_as_sf(coords = c("long", "lat"),
           crs = 4326)

df_rast <- st_rasterize(df)

ggplot() +
  geom_stars(data = df_rast)

ggplot() +
  geom_stars(data = df_rast,
             na.action = na.omit)