is there anywhere i can get updated email templates for SCA? That include correlated items or anything like that? Or do i need to buy a 3rd party platform like Bronto or something like that?

You might not need to add a third party platform but at the bare minimum you'll need to roll your own template development. Emails are indeed quite basic by default.

Which version of SCA are you on? item_relations_correlated.tpl is included on the SuiteCommerce Base Theme