Question on EK and lvl 4 Spell Slot

Been working on a build today for a type of elemental spell sword character that I’d prefer to be mostly built around the EK War Magic mechanic. Problem with it is I was really hoping to get at least 1 lvl 4 spell slot. Off of the top of my head I don’t think this is possible with multiclassing in any way but wanted to ask a bit more seasoned builders. Thanks for the help ahead of time.