Probably the question is what do you find that is limiting your using the Shopify admin for adding products etc?
We operate a product management platform where you can build and edit your products before assigning them into a group that then pushes into your Shopify store. We have a pipeline where you can move products depending on what data still needs to be entered.
Let me know the answer to first question as that way can guide you better. If you want to check out our platform and have a demo just send me an email to email@example.com
We also customise our platform for each client if they need it as we find that everyone has different processes and requirements in terms of product fields, data flow etc.