is there a way to create 2 different forms: one for editing a row and another for adding a new row?
Several ways.
The default system-generated Add and Edit actions will automatically open the most prominent* form view for the table/slice that it is triggered from. By “prominent”, I’m referring to a hidden selection system that the app uses to choose a form/detail view when there are multiple possible choices. The system-generated views are the lowest priority, and any user-generated views are a higher priority. That means the difficulty is if you manually create a 2nd form view, now both actions will open that new view.
So one way to fix this is to create your own Add and Edit actions, using LINKTOVIEW or LINKTOROW to open the exact view that you want.
A way that I often employ is to create a new slice whenever I need a new custom detail or form view. That way all I need to do is create a single new action for opening that one view, while leaving the default systems in place.