edit change the default filesystem in config/filesystem.php

i did this, but still saves the caches & stuff in storage folder locally

You can configure the filepaths to use for cache and sessions in the relevant config files, but I don't think you will be able to store these on the S3 without editing the Laravel core. Using S3 for cache and sessions would be a huge performance hit anyway, it would be better to use the database, redis or memcache if you're not able to use the filesystem.

Ideally you really wouldn't want to be using the filesystem for such things on production anyway, database is much faster.