I think your confused about what a blitz is, a blitz is just a sudden surprise attack that couldn’t really be countered, the terms not for initial attacks only. For ex. Sakura blitzed shin, and it was her initial attack, the surprise helped her blitz him. On he flip side, sasuke blitzed madara when he cut him in half, and that was in the middle of a fight
Also, why is minato solely restricted to marking his actual opponent to be effective? He’s fully able to mark whatever he touches, including spots he’s touching while avoiding someone or something. Ex. If he’s in cqc, and his hand happens to touch the floor as he’s being driven back, he could place a seal on the ground as he’s being pushed back, and just teleport to the spot once the opponents passed it, effectively now being behind him by surprise. This is even nastier if they’re fighting in wooded areas and whatnot, not so much in like.. a desert.
Those fodder on the battlefield in the 3rd war? Blitzed
Granted, I don’t know the context of the threads your mentioning. But an ftg blitz is possible, just not as an initial attack unless minato has already prepped or marked somewhere in the area before.
Hell technically anyone with teleportation can blitz someone