There's still the Kang Dynasty movie to come.Are we skipping over Iron Lad? He is suppose to be the young version of Kang the Conquer.
Also, I believe Iron Lad is mostly a character in use for a complicated Kang timey wimey story arc. His time as an Avenger is bound to that and transforms later out of that persona.
Whereas Riri's Iron Heart, is just a straight up passing-of-the-mantle-ish of Iron Man.