@advancingaiden You've probably already found a solution. But just in case you haven't, I just stumbled across Website Toolbox.
They don't have a Shopify app in the app store, but they do offer an easy way to embed the forum into your Shopify website. Also, for a one time $149 they'll setup single sign on integration with your Shopify website so your shoppers won't need to create an additional login for your forum.
I have not used Website Toolbox yet, but I'm considering using it for an upcoming client project.
I hope this helps!