What Nehz has brought up shows that currently the Resistance Negation stuff for cards is already accepted and all, but the layers discussed on the OP are still currently at debate here.
Anyways...
Ok and? You do realize that you're arguing the card mechanics is canonical in the story, meaning that the shadows beating out sora's attacks due to the card system is canonical, so either its not canonical and Sora can still oneshot them no matter what cards they have, or the card system is canonical.
The card system is entirely unrelated with an opponent's power and we've seen many times that superiority or comparability still apply even with the card system at play. All the card system does canonically is change
how people fight and that's it. Saying that a Shadow is able to fight with Sora canon-wise because of the card system requires sustainable evidence and not assumptions that stem from nothing.
Even as seen in the OP,
Axel was able to one-shot Vexen, and
Lexaeus was able to initially overpower Riku despite your logic implying that everyone who's part of the card system are on equal footing and it's their wit that allows another opponent to combat another. At the very least the card system doesn't cover a card wielder's power, and it solely pertains abilities and how fighters interact on the battlefield.
So just having higher potency because the bigger number cancels out the smaller one, that's literally what your video explains for the card system. How exactly is this resistance negation because you're using a stronger card to stop a weaker card.
Just not understanding the card system then?
Explain this video that you're using to argue resistance negation where it's literally saying the bigger number cards nullifies the smaller ones. Because either he's wrong or you're not doing a good job explaining the card system at all.
May I ask where is "higher potency" coming from in the video to begin with? That's something you derived from
your personal observation, what actually is shown is that a Lv2 card overpowers a Lv1 card (two completely unrelated cards at that).
The "numbers" on the card have nothing to do with the power, but merely value (We can prove this by the fact you can "break" attack cards with a magic cards, break friend cards {Which is merely just bringing a friend of Sora into the battlefield} with attack cards, or even break item cards {Which is just Sora using an item in battle} with a friend card)
It's Resistance Negation because higher valued cards work on lower valued cards regardless of what their effects are. Lethal Frame, for example, is able to negate the resistance to time stop, and it stacks up from there (BTW, the card isn't explicitly a "higher potency" time stop spell, it's considered that because of its effects; This isn't like FF where spells progress linearly)
This isn't the only card like this and this applies to cards with higher values in general. The Keyblade card has the normal effects of the Keyblade, alongside the other cards having light and darkness concepts tied to them (which comes with the normal haxes they have in-universe) yet things normally resistant to these things are still prone to being effected if their card is of a lower value
In other words, there's nothing to suggest that the higher value and lower value correlates to power or potency (if anything, there's stuff that goes against that as mentioned above) but merely abilities and how one interacts on the battlefield. Additionally, cards negate the resistances that opponents normally have if the user has an higher valued card
If this keeps going on I think it'd be worthwhile to ask other staff on input at this point, as I don't think my stance, or Glassman's stance is going to change anytime soon.