Will deleting products or collections from my Shopify store affect SEO?

Yes, if you delete a page from Shopify you should also delete the index page on google. This is the right way to do it instead of hiding or redirect. Let me explain, Every product and every collection have their own page and a unique URL (web address). Google and other search engines index your store's pages and show them in relevant searches. If you delete an item or an entire collection from your Shopify store, their page is removed but Google doesn't necessarily know that the page no longer exists. So, a user can perform a search and your deleted page may appear on the search engine results page. Then when the user clicks on the result she will reach a broken page or be redirected to a different page. Since Google wants to provide users with the best results for their searches, and your Shopify store has broken links or pages that don't exist anymore, your ranking will be affected accordingly.

Is Shopify Bad for SEO?

No, it's not. But if you don't delete your products the right way, it affects your Shopify SEO indirectly. In such a case, your potential customer will land on a 404 error page, which declines the customer satisfaction and experience rate. Since they both are ranking factors, your SEO is ultimately affected.

Explanation

Think of it from the user's perspective. You searched for a product, and Google showed you relevant results. You clicked on one product page you're willing to buy, but NO!!! The link is broken. You don't feel good about it, do you? Since Google prioritizes customer satisfaction first, Google is also unhappy with this situation. Thus, the next time Google is asked the same search query, it shows other relevant pages that won't upset its users.

The Right Way to Delete Your Products

Whenever you're deleting your products from your Shopify store, make sure to delete their index page on Google. Use a crawler to find any internal links to 404 pages and remove them. You can set up 301 or 302 redirects from all your inactive Shopify collection pages. In some instances, leaving the product without the "Add to Cart" button and a redirect link to the closest product category or the home page is also a good idea. By doing so, your Shopify SEO won't be compromised.

Well, the process of deleting your product page doesn't hurt your website ranking anyhow. However, if your web page has been crawled by Google bots, it's appeared in search results, and even if your page is deleted, it's still in SERP. So, you should set up 301 or 302 redirect.