I was able to use this script to normalize mp3 files in my Android device, but I can't guarantee that it will work on every Android device. Regardless, I will detail the steps I took for my device running Android 7.0 Nougat to normalize mp3 files in an Android device and still leave Most Played, Recently Played, Recently Added, and playlists intact.
** Before you attempt to normalize your music files, I recommend you to do the following test: **
Step 1.) Go to your Most Played and find a song that you will use as a test (preferrably one you don't really care about if it gets messed up)
Step 2.) Put that song in a dummy/test playlist.
Step 3.) Copy that song from your Android device to your computer.
Step 4.) Normalize the song you just copied onto your computer with "normalize_to_95db.bat"
Step 5.) Copy the normalized song back to your Android device, overwriting on the un-normalized older copy.
Step 6.) If the song is still your dummy/test playlist, Most Played, etc., it's probably safe to continue to "Normalizing"
Step 1.) Copy your ./Music/ folder from your Android device to your computer.
Step 2.) Normalize the folder on your computer with "normalize_DIR_to_95db.bat"
Step 3.) Copy the normalized .mp3 files from the /Music/ folder from your computer into the ./Music/ folder in your Android device, overwriting on the old songs. That's it.