htaccess重写不重定向

Would greatly appreciate help on the following.

Am building an app and want to avoid IDOR (insecure direct object reference).

https://example.com/folder1/index.php?folder2=Xyz&filename=Abc&variable=Pqr

Using htaccess in "folder1" I want to rewrite the above URL into a clean url ending with folder1 name.

I tried the following and it does not work

Options +FollowSymlinks
RewriteEngine on
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^/index-([a-z]+)-([a-z]+)-([a-z]+) https://example.com/folder1/index.php?folder2=$1&filename=$2&variable=$3 [NC,L,QSA]

Thanks in advance for all your help!