minato is a tier above Itachi.
Itachi would need to be an edo in order to stand a chance. Else, minato just dodges all of Itachi's attacks and forces susanoo until Itachi's stamina gives way.
Minato's clones can even use and place FTG markers. And if all else, frog song + playing on the defensive = gg.
Ofc itachi would solo minato.
Itachi is god of shurikens and kunai jutsu, no marked kunai will ever get near him.
Minato throws kunais, itachi deflects kunais with shuriken. Minato picks up and throws kunais again, itachi gets blitzed.
Even if minato just leaves his deflected kunai there, how in the world does that = a win? Itachi can't even hit minato, and his MS techniques massively drains his stamina while FTG doesn't.