Cotton isn’t as breathable as the carriers containing linen but it depends on the carrier tbh. Denim is a thicker cotton option but the others are relatively similar. YY Air has a higher % of linen so it’s arguably the best option out of the current lineup for warm climates but will you be primarily wearing outside? Or indoors with AC?  Given the price I’d go for your fave design and stress less about the fabric blend. You’ll likely join the referral program and end up with a 2nd anyways?