Welcome to Shopify Community. My name is Olivia and I work here.
I appreciate your question and I'd be glad to help guide you in the right direction. I wrote a similar forum post on helping you find issues in your theme, and narrowing them down to an app here. A little more than halfway down the page I mention:
If you suspect an app is causing the issue, you can uninstall the app by following the uninstall instruction from the app to ensure you are properly removing it. Oftentimes, removing an app from your Admin (Admin >Apps > Delete app) is not enough, as apps can leave trails of codes behind in the theme code. If you are having issues with uninstalling an app, we recommend reaching out to the app developers directly for assistance.
I highly recommend connecting with the app devs for the most accurate advice around where their app injects code/scripts, but I would suspect to find it in your liquid product templates in addition to your theme liquid. A cool hack you can use is a free online tool such as Diffchecker to compare a modified file against an original file. This will show you all of the code changes that have been made and further help you narrow down where the code lives.
To make things a bit easier for you, I pulled up the email address for the Yotpo app review team here: email@example.com.
If you have any further questions, don't hesitate to connect with me.
1. Download this Google Chrome Extension: (you need to use Google Chrome).
2. In your Shopify Admin, go to Online Store > Themes > Edit Code
3. In the new box that appears with the extension (top right corner) search for whatever code that you're looking for, like yotpo on this case. It will show you all the occurrences (if there any).
Let me know how it goes.