Studio is limited for this kind of action. 

Development is needed because simply changing the status of the order with an automated action doesn't produce the same action as the 'Confirm Order' button. We need to add a server action to trigger all the actions normally involved when you click on the 'Confirm' button. Without the server action, there won't be any 'Delivery Order' / MTO / Purchase order / Project ... created behind the order. 

Odoo and studio are complex even if they appear as super easy and user friendly.