The only version of Minato stronger than Itachi is Edo Minato.
Minato isn't stronger than Itachi, he simply the ability (ftg/speed) to avoid majority of his techniques. On paper, Itachi is the clear victor but an actual battle can sway.
If Itachi can't land an attack on Minato (even because of ftg) he is weaker than him. Simple as that.
Minato can't get pass Susanoo.
If Itachi can't land an attack on Minato (even because of ftg) he is weaker than him. Simple as that.