Here's a script from GPT4:

#!/bin/bash

# Create a temporary file for storing file checksums
tempfile=$(mktemp)

# Generate MD5 checksums for all files in the current directory and its sub-directories
find . -type f -exec md5sum '{}' \; | sort > $tempfile

# Detect and delete duplicates
awk 'BEGIN {
    lasthash = "";
    lastfile = "";
}
{
    if ($1 == lasthash) {
        print "Deleting duplicate file: " $2;
        system("rm -f \""$2"\"");
    } else {
        lasthash = $1;
        lastfile = $2;
    }
}' $tempfile

# Clean up
rm -f $tempfile

This script can be run with Termux from the root of your internal storage. Usually /sdcard or /storage/emulated/0. Do not confuse this with running from root if you are rooted.

Before using a script that interacts with your files you should backup anything that is important just in case.

Furthermore, if you comment out:

system("rm -f \""$2"\"");

By adding a # in front of it like this:

# system("rm -f \""$2"\"");

You can run the script and see what files the script would delete without actually deleting them. I would recommend doing this as I have not tested this script.