You want to avoid cup and cone bearings on mountain bike, or any bike for that matter in my opinion.
I had a set a of bitex road hubs on a recent road bike that I just sold with thousands of miles on them. Also have a Bitex hub on my 27.5+ wheelset for my mountain bike. No problems at all. Bitex has been around for a long time and they make quality hubs.
BITEX
https://www.speedgearbike.com/439084750