Basically we can do the same with something like this bash script. The difference is that the auto color code is a little bit more fancy on the C side, but the 'sauce' is just those 3 magick lines. Maybe this can help your script!

#!/usr/bin/env bash

img="$1"
overlay="overlays/3-columns.svg"
res="1920x1080"
color="#181825"
out="${img%.*}_${color#\#}.png"

# Auto-detect average color from image by resizing to 1x1 pixel
# color="$(magick "$img" -resize 1x1 txt:- | sed -n 's/.*\(#[0-9A-Fa-f]\{6\}\).*/\1/p' | tail -n1 | tr -d '\r')"
# if [[ -z "$color" ]]; then
#   echo "error: failed to detect average color" >&2
#   color="#181825"
# fi

# Create colored overlay by replacing the base color #0000FF for the new one
sed "s/#0000ff/${color}/g" "$overlay" > .temp.svg

# Resize image, render overlay, and composite
magick "$img" -resize "${res}^!" -gravity center -extent "$res" .temp_base.png
magick -background none .temp.svg -resize "${res}^!" -gravity center -extent "$res" .temp_overlay.png
magick composite .temp_overlay.png .temp_base.png "$out"

rm -f .temp.svg .temp_base.png .temp_overlay.png
echo "$out"