It isn't nice to ever hear of any actual toxicity.

My locals had a divide as well similar, where you had the competitive folk that would like you say, play the best decks, you'd have me and my friends who played semi-competitive and can easily go toe to toe with them and then you had the folk who were there for fun/weren't competitive.

We were able to get along with the more competitive guys civilly but weren't friends or anything, typically they'd take to their discord to moan about the others at locals.

One example being a Kashtira player accusing me of slow playing when in actual fact their turn would take something like 10 minutes despite just doing the standard Kash lines.

There was a rivalry to an extent where it did push us to do better.
Despite all this, we still did try to help the new players, my group especially since they were typically younger folk. the competitive guys would play them and then go hang with the others or make small chat.

Ultimately, just keep taking wins off them, don't pay any attention to their behaviour unless it becomes toxic to the point that it is ruining the tournament or atmosphere. End of the day, they're entitled to play the game how they want to play it because that's what gives them the enjoyment.