A simple patchwork of ggplot has left me uncertain how to locate the legend in the overall figure.

Here’s the data and the two plots

library(tidyverse)
library(patchwork)
library(magrittr)

set.seed(123)

t1 <- expand_grid(
  rs = 1:2,
  fac = 1:5,
  grp = 1:2
  ) %>% 
  mutate(
    y = runif(20),
    row = fac %>% 
      is_in(1:3) %>%  
      ifelse(
        1, 2
      )
  )

p1 <- t1 %>%
  filter(
    fac %>% 
      is_in(1:3)
  ) %>% 
  ggplot() +
  geom_point(
    aes(
      rs, y, color = factor(grp) 
    ),
    size = 3,
    position = position_dodge(width = .4)
  ) +
  facet_wrap(~fac, nrow = 1) +
  theme(legend.position = "none")

p2 <- t1 %>%
  filter(
    fac %>% 
      is_in(1:3) %>% 
      not
  ) %>% 
  ggplot() +
  geom_point(
    aes(
      rs, y, color = factor(grp) 
    ),
    size = 3,
    position = position_dodge(width = .4)
  ) +
  facet_wrap(~fac, nrow = 1)

But I want the legend in the blank panel on the bottom row (next to the 5 facet and underneath the 3 facet)

I tried

p1 / p2 +
  plot_layout(
    design = "
    AAA
    BB#", 
    # CC#
    guides = "collect"
  ) &
  theme(
    legend.position = "inside",
    legend.position.inside = c(5/6, 1/4)
  )

To no avail.