It's tough to definitively say whether Shopify is bad for Google Shopping, since it really depends largely on how you choose to use Shopify.
On one hand, Shopify stores make it relatively easy to customize and build your store according to your needs, which can be a great boon for Google Shopping. This is because the platform offers specialized features that are perfect for setting up an online shop and crafting SEO-friendly descriptions. You can also easily link to pages with product information, images, and descriptions that Google Shopping can use to include your products in their search results.
Overall, it really depends on how familiar you are with Google Shopping and Shopify and how much effort you put into setting it up. If you put in the time and resources, you can definitely get great results with Shopify and Google Shopping.
For more info on this topic, check out this blog post from Shopify: https://www.shopify.com/retail/connect-your-shopify-store-to-your-google-shopping-campaigns