Switching from Shopify to WP, what do I need to watch out for before switching?

I’m currently using a test domain (fashionfatale.co) to make/test a new storefront for my actual store (which has a completely different domain, let’s call it XX.co).

I’m worried that if I add a bunch of products to the test site, then push the test site to the live site, that something will break and customers won’t be able to get their orders fulfilled (perhaps there’s some key that links fashionfatale.co to this aliexpress plugin that will break when I switch domains, because it doesn’t recognize XX.co as the new site?).

I currently use Zendrop/Shopify on my live site, XX.co. Should I delete Zendrop (the app/widget that currently fulfills aliexpress orders) on Shopify side before switching?

So please let me know what to do/what to watch out for before switching domains, and if there’s anything that would break & how to prevent that, especially if I missed something.