Orphan product pages and orphan canonical links

[bargainforyou]

Hi everyone!
After changing the theme of the site, we encountered the following problem:

product pages are available at different URL addresses, depending on the categories they belong to. 

For example, the product card with the original URL https://bargainforyou.com.au/products/the-shell-art-deco-mirror  is technically an orphan because there are no incoming links to it, the user cannot get to it when navigating the site. Instead, the user can navigate to the same product card at a different URL: https://bargainforyou.com.au/collections/art-deco-mirrors/products/the-shell-art-deco-mirror  

These extra nested pages have canonical links to the original product, but because they are orphaned this can be ignored by search engines. We have crawling errors with original product pages that are orphaned. How have you solved such a problem?