I find it hard to understand how a Shopify Partner continues to insist on something that is factually incorrect. You keep repeating “generally digital goods are not accepted”, without providing any facts to back up this. So for the sake of clarity of other readers of this post, let’s provide them with products that Google Shopping clearly does not support, as per their official link!
https://support.google.com/merchants/answer/6150006?hl=en-GB
At no point, they ever mention that ‘digital goods’ are not accepted, so please stop providing information that is not factually accurate.
I have also been on the phone with a Google Representative today and they mentioned the problem of the missing attribute relates to Country! She mentioned that the feed needs to clearly specify the country, so Shopify needed to add this column to the feed, so we can specify it! Your solution does not help at all because there is no problem with the shipping itself - it accurately is marked as free shipping already - the missing sub-attribute relates to country. So Shopify needs to do something about this!! I have been in touch with Shopify support clueless about this issue and always end up telling me to contact Google, which obviously is always the easy way out when you don’t know what to do, definitely better support needs to be given to Shopify merchants. We are just left hanging without any support and any solution.