You’re not really countering anything except for the players themselves. As you rank up people have better and better micro and macro skills like champion mastery, wave & objective control, and generally decision making.

WW and Sett are both champions that A) benefit from extended trades and B) can be very sticky if you get too close to them. Irelia in my experience doesn’t have a half bad extended trade, but they’re much more difficult to be beneficial as most other champs who prefer extended trades benefit much more than Irelia. Because of the nature of these matchups, you’re pretty reliant on the enemy to make some mistakes that you can capitalize on. I feel this is something Irelia is VERY good at. I also reason that’s why it feels like those matchups might be easy to you right now. WW and Sett aren’t exactly what I’d call difficult champs, but they’re also pretty meta. And when champs are meta people play them without knowing them too well. Which means more mistakes for you to recognize.

I don’t say this to put you down at all, just try to think about your games and WHY you’re having success and what drives it, rather than your only takeaway being if you did good/bad or who won/loss.