The Cura slicer from Ultimaker has a setting to enable that kind ironing on top surfaces although just with the regular nozzle but it works surprisingly well!
Oh yes, that’s where I got the idea, I don’t do smart.
Tool changer from e3d, ironing from cura, lollipop tools from the cnc industry.
Actually with a nozzle that has a rounded profile you wouldn’t even need a tool change... that could be cool.
the part fan placement is an issue, you might have a silicone sock, that's why I didn't want to go this route.
Well I admit the toolchanger would be more effective, but as a budget option the rounded nozzle could be nice.