I don’t understand the seemingly widespread love of cotton clothing for outdoor and athletic endeavors. It’s super slow drying after getting wet with sweat, rain, etc. It’s useless for retaining warmth in cold weather. It retains body odor more than any other fabric. What is good about it? Its “breathability?” That’s way overrated.
Modern synthetics dry very fast, don’t retain odors, can retain warm well in cold weather (depending on how it’s made), and can provide excellent sun protection (again, depending on the particulars of the fabric).
Merino wool is even better than synthetics in many situations and better than cotton in almost every situation. (Excluding dress and casual shirts for business/leisure/ casual wear, which we’re not talking about here.). Merino is lightweight and cooler than cotton and most synthetics in hot weather. It’s way warmer than cotton and most synthetics in cold weather. It doesn’t “feel” wet until it’s really soaked because it’s hollow fibers wick moisture from your body. Best of all, merino doesn’t absorb odors. I sweat more than anyone I know (as my son says, “you sweat when you read, Dad”) and I can wear a merino t-shirt for several days in very hot weather with it remaining odor-free the entire time. It also drys much faster than cotton (though not as fast as synthetics).
If you want buttons and pockets, get a high-performance synthetic fabric. If you don’t need those, wear merino t-shirts with short or long sleeves.