So are you trying to point out that we have no information about the other cards in the pack besides the one guaranteed 84+ overall card? If so, then I think I'm starting to understand your point. But I still don't think it's deceptive.
You are still saying that it looks like ALL cards in the pack are 84+ overall even though it says that it only guarantees ONE 84+ overall card and you claim to understand that. I still don't understand why you think it looks like that.
The thing is that there is no minimum overall for the other cards, which means that those cards can be any overall from 60 to whatever the highest overall is at the time of opening the pack. That is the information we have.
When there is a minimum overall that applies to all cards in the pack, it is usually mentioned in the name and/or description of the pack. And that's how I think it should be. For example "4x 79+ OVR players pack".
And no, it's not just an assumption that the pack contains lower overall cards. It is almost guaranteed. Based on the information we have, it is theoretically possible that all cards in the pack are 84+ overall if you get incredibly lucky, but it is almost guaranteed to contain lower overall cards besides the one guaranteed 84+ overall card.
Maybe they could be a bit more informative with some packs. For example when they advertise a pack with a "higher chance" to get a specific type of card, they could tell us what that "higher chance" actually means. But as I said, I still don't think they are deceptive with the probabilities and pack descriptions.