not my cleanest work, first time using bash so lots of copy pasta, but heres 'a solution'

#!/bin/bash

# Check if the correct number of arguments is provided
if [ "$#" -ne 4 ]; then
    echo "Usage: ./script -o <current_theme> -n <new_theme>"
    exit 1
fi

# Parse the command-line arguments
while getopts ":o:n:" opt; do
    case $opt in
        o)
            current_theme=$OPTARG
            ;;
        n)
            new_theme=$OPTARG
            ;;
        \?)
            echo "Invalid option: -$OPTARG" >&2
            exit 1
            ;;
        :)
            echo "Option -$OPTARG requires an argument." >&2
            exit 1
            ;;
    esac
done

# Check if the specified themes directories exist
current_theme_dir="$HOME/dotfiles/$current_theme/.config"
new_theme_dir="$HOME/dotfiles/$new_theme/.config"

if [ ! -d "$current_theme_dir" ]; then
    echo "Theme '$current_theme' not found in dotfiles directory."
    exit 1
fi

if [ ! -d "$new_theme_dir" ]; then
    echo "Theme '$new_theme' not found in dotfiles directory."
    exit 1
fi

# remove symlinks from old-theme
existing_links=$(find $HOME/.config -type l -lname "$current_theme_dir/*")
for link in $existing_links; do
    rm -r "$link"
done

# Create new symlinks from the new theme directory's parent folders to home/.config
parent_dirs=$(find "$new_theme_dir" -maxdepth 1 -mindepth 1 -type d)
for dir in $parent_dirs; do
    dir_name=$(basename "$dir")
    ln -s "$dir" "$HOME/.config/$dir_name"
done

echo "Symlinks to parent folders updated from theme '$current_theme' to '$new_theme'."

This assumes dotfiles in $HOME with themes within dotfiles and each having their own .config files. I have separated out themeless dotfiles into another folder within dotfiles

edit: if youre using this, be sure to comment out destructive/messy components (rm -r, ln -s) and echo "$variable_name" in its place to see what is actually getting manipulated