leaflet: different colors of addMarkers for each group/layer

Question

I am trying to replicate the answer to this question, but with a) addMarkers instead of addCircleMarkers, and b) with a distinct color for each group. Below my reprex. Unfortunately, I am struggling to get different colors for each group. Grateful for any hint. Many thanks.

library(tidyverse)
#> Warning: package 'dplyr' was built under R version 4.1.3
library(leaflet)
#> Warning: package 'leaflet' was built under R version 4.1.3
library(RColorBrewer)

df3 <- structure(list(id = 1:20, groupID = c(
  277698L, 277715L, 277704L,
  277706L, 277705L, 277705L, 277719L, 277705L, 277705L, 277709L,
  277706L, 277705L, 277704L, 277706L, 277715L, 277702L, 277719L,
  277706L, 277715L, 277706L
), lat = c(
  -10.8172615660655, -10.8904055150991,
  -10.8887597563482, -10.90203509, -10.9001514, -10.8997748900025,
  -10.8960177351343, -10.8896179908615, -10.8991450456802, -10.9224848475651,
  -10.9000373151094, -10.8905013650562, -10.8889438100208, -10.9001234797436,
  -10.8861897462579, -10.9326053452642, -10.8916601751623, -10.902075281944,
  -10.8822231928033, -10.9079483812524
), lon = c(
  -36.9248145687343,
  -37.0665064455395, -37.0921721937304, -37.05829295, -37.0969278,
  -37.0976847916125, -37.0840372102666, -37.0963566353117, -37.0945971936751,
  -37.0549293249471, -37.066113628594, -37.0940632483155, -37.095505683692,
  -37.0590422449149, -37.0782556623101, -37.0698746017798, -37.0841003949028,
  -37.0593363285999, -37.0724709841895, -37.0817244836096
)), .Names = c(
  "id",
  "groupID", "lat", "lon"
), row.names = c(
  20L, 23L, 8L, 36L, 14L,
  13L, 16L, 2L, 11L, 1L, 26L, 6L, 5L, 31L, 22L, 50L, 17L, 34L,
  25L, 42L
), class = "data.frame")

groups <- unique(df3$groupID)
length(unique(df3$groupID))
#> [1] 8
vec_cols <- brewer.pal(n = length(unique(df3$groupID)), name = "RdBu")
names(vec_cols) <- unique(df3$groupID)

fn_marker_color <- function(x) {
  
  vec_cols <- brewer.pal(n = length(unique(df3$groupID)), name = "RdBu")
  names(vec_cols) <- unique(df3$groupID)
  
  vec_cols[x]
  
}

icons <- awesomeIcons(
  icon = 'ios-close',
  iconColor = 'black',
  library = 'ion',
  markerColor = ~fn_marker_color(g)
)

map <- leaflet(df3) %>% addTiles(group = "OpenStreetMap")

for (g in groups) {
  d <- df3[df3$groupID == g, ]
  map <- map %>% 
    addMarkers(
    data = d, lng = ~lon, lat = ~lat,
    icon=icons,
    group = g
  )
}
map %>% addLayersControl(overlayGroups = groups)
#> Input to asJSON(keep_vec_names=TRUE) is a named vector. In a future version of jsonlite, this option will not be supported, and named vectors will be translated into arrays instead of objects. If you want JSON object output, please use a named list instead. See ?toJSON.
#> Input to asJSON(keep_vec_names=TRUE) is a named vector. In a future version of jsonlite, this option will not be supported, and named vectors will be translated into arrays instead of objects. If you want JSON object output, please use a named list instead. See ?toJSON.
#> Input to asJSON(keep_vec_names=TRUE) is a named vector. In a future version of jsonlite, this option will not be supported, and named vectors will be translated into arrays instead of objects. If you want JSON object output, please use a named list instead. See ?toJSON.
#> Input to asJSON(keep_vec_names=TRUE) is a named vector. In a future version of jsonlite, this option will not be supported, and named vectors will be translated into arrays instead of objects. If you want JSON object output, please use a named list instead. See ?toJSON.
#> Input to asJSON(keep_vec_names=TRUE) is a named vector. In a future version of jsonlite, this option will not be supported, and named vectors will be translated into arrays instead of objects. If you want JSON object output, please use a named list instead. See ?toJSON.
#> Input to asJSON(keep_vec_names=TRUE) is a named vector. In a future version of jsonlite, this option will not be supported, and named vectors will be translated into arrays instead of objects. If you want JSON object output, please use a named list instead. See ?toJSON.
#> Input to asJSON(keep_vec_names=TRUE) is a named vector. In a future version of jsonlite, this option will not be supported, and named vectors will be translated into arrays instead of objects. If you want JSON object output, please use a named list instead. See ?toJSON.
#> Input to asJSON(keep_vec_names=TRUE) is a named vector. In a future version of jsonlite, this option will not be supported, and named vectors will be translated into arrays instead of objects. If you want JSON object output, please use a named list instead. See ?toJSON.

^{Created on 2022-04-20 by the reprex package (v2.0.1)}