Exofficio have been a leading brand for hiking underwear in the US for years.
I am a firm supporter and user of the IceBreaker brand of undies. Although they do wear out quickly. Macpac also do a good merino undies product, but probably less durable than IceBreaker. Recently I discovered
Massdrop
Massdrop had these undies available as a 2 pack at $US34 - normally $US52.
I couldn't resist trying them. Yes, they have lived up to all the hype! Comfortable, light and breathable, no smell and stylish, You can also get these in a brief version if you don't care for the boxers.
https://www.exofficio.com/give-n-go-boxer-2-pack/1241-2179.html
The Massdrop deal is over now, but I suggest you join this lightweight hiking group and you will get some good special alerts on many lightweight hiking products - Darn Tough socks was another special I hooked into a few weeks back