Regarding chafing from tech fabrics, there are significant differences between my various poly wicking tech fabric t-shirts. My lowest price Champion long sleeve UV resistant tees might chafe nipples and moles a bit for some folks. I don't any manboob nipple chafing issues since I was a teenager, but after too many years of sunburns I have various moles on my torso that chafe easily and ooze a bit of bloody serous fluid. I've noticed a few of those spots on my long sleeve Champion tees. (Yeah, yeah, I need to check with a dermatologist, it's on my increasingly long list of old dude medical maintenance stuff. Sheesh. The human body sure wears out quickly. I'm gonna have a word with the manufacturer some day.) So I'm pretty picky about shirts.
The Champion Vapor tees are better, with a slick, smooth, soft and very comfortable wicking fabric that doesn't chafe. Costs around $15-$20, less expensive than Under Armor tees that use similar material. Reinforced neck too. I found a similar tee at Ross or Marshall's that's just as good for about $5, but can't tell what the brand is -- there's an "A" shaped logo and "qwick dry" on the label, made in Egypt.
No problems with the old Pearl Izumi Transfer Minerale fabric, but they don't make those anymore. Too expensive. But you can buy baselayers from the same material from serious mountaineering/hiking shops. The fabric is impregnated with carbon or charcoal and maybe silver to resist odors longer. The material is more like a tight knit, thin but slightly spongy feeling, very stretchy and incredibly comfy in all weather, hot or cold, damp or dry. Puts most wicking fabrics to shame, including merino wool, but it's pricey stuff.