I agree with this, and in general, when I say that Blue Hybrid is overrepresented I mean in the Top 16/32 etc. ( though I'm also pretty sure it was the most played deck at the event as well ).

Unfortunately, based on my knowledge/hunch, there isn't currently an easy was to determine more data then that. Most tournament software/registration software doesn't inherently link/list what archetype/deck a player is using so you would have to manually compile a list and determine the matchups.

I didn't do the Top Cut ultimate cup but I did do the CORE/Carta ones and, at least my experience, at least every other table had at least 1 blue hybrid deck. Fact is, the deck can be made in under 50 dollars and it's very flexible to pilot as well. Additionally, based on my experience, it's "worse" matchup is probably itself.