Hi there, @storeowner123.

I appreciate what you've done so far in connecting Shopify balance to QuickBooks Online (QBO). If you weren't able to search for the Shopify app in QBO, that means it isn't supported yet. With this, I recommend contacting Shopify application and request to enable the integration.

Moreover, you may check API (Application Programming Interface) if they're currently having any system maintenance so we can ensure you'll be assessed with this issue. 

In addition, you can refer to this article to learn more about disconnecting third-party apps to QBO: Disconnect an app and change subscription.
 

Please don't hesitate to reply to this thread should you need additional assistance connecting third-party applications to QBO. I'll be here to help you, 24/7.