I did some digging before I made this post. There is a similar question asked and Shopify customer service responded saying that they could put in requests but there’s no promise what happens in development. Many of the users in your Shopify community were unhappy, as you can read for yourself:
https://community.shopify.com/c/Shopify-Discussion/Disable-order-confirmation/td-p/493291
You say that this option works as-is for 90% of your customers; are you saying the other 10% serve an insignificant portion of Shopify’s incoming revenue? Is there no way to just assist us in turning this setting off permanently for our shop? I suppose we will put in a request for adding this feature, but if I can give no estimated time of delivery on such a feature then you’re not really providing us with anything we need in this situation.
Are you going to allow 10% of your customers to be unhappy with the functionality of their Shopify store? If so, I guess I can’t expect anything to happen for us and we will pursue a drastically more costly and time-consuming solution. Not sure why we would be forced to take that path, but you aren’t assisting me with any workable solution.
Please put in the request for the feature, but without knowing if or when it could possibly be implemented it really doesn’t make much of a difference. Thank you for your time, but we remain unsatisfied with your response.