Zardnaar
Legend
Upcasting explicitly requires a slot. The wording would need to be along the lines of "Pick an artificer spell you can cast with a level 1, 2, or 3 slot."
It's not. And without that, you can't have anything upcast.
Just like you can't pick an upcast spell as a spell known. Not that you wouldn't want to (though you wouldn't), but you can't.
Aware. At a glance thats where the confusion is coming from.