I would like to remove the white background that is created around the world map when plotting in Mollweide projection using theme_bw() as a base, in R. This is my code:

library(pacman)
p_load(terra, ggspatial, ggthemes, sf, tidyverse, viridis, cowplot)

# load world map
wrld <- ne_countries()

# reproject to mollweide
wrld_moll <- project(terra::vect(wrld), "+proj=moll +lon_0=0 +x_0=0 +y_0=0")

# transform as sf
wlrd_sf <- st_as_sf(wrld_moll)

# plot
p1 <- ggplot() +  
  
  # add world as a background
  geom_sf(data = wlrd_sf, fill = "grey90", col = "grey60", linewidth = 0.25)  +
  
  # add theme map 
  theme_bw() + 
  
  # personalize theme
  theme(axis.title = element_blank(),
        panel.border = element_rect(fill = NA,
                                    colour = "#238B45",
                                    linewidth = 2,
                                    inherit.blank = T)) 

p1

Which gives this map (I pasted the map on a blue background to show the difference with the next one):

I try to remove the background by adding these lines to my personalized theme:

p2 <- p1 +   theme(axis.title = element_blank(),
                   plot.background = element_rect(fill = "transparent",
                                                  colour = NA_character_), # necessary to avoid drawing plot outline
                   panel.background = element_rect(fill = "transparent",
                                                   colour = NA_character_), # necessary to avoid drawing panel outline
                   panel.border = element_rect(fill = NA,
                                               colour = "#238B45",
                                               linewidth = 2,
                                               inherit.blank = T)) 

Which removes also the background of the world (eg seas, oceans), not only the background between the world and the panel:

What I would like is those areas between the world map and the panel border (where I have put a blue big dot) to be transparent, but keeping oceans and seas white.

I think it is some theme_bw() setting but so far I cannot find/change it.