The problem with your X-Cal is that it has old-school XC geometry. XC geo bikes climb well but are lousy descenders and are twitchy everywhere else. You need a bike with modern progressive geometry and I also think that Hardtails are best with 29×2.6 tires. Check out these bikes.
These Hardtails would be my first choice.
Specialized Fuze
Rocky Mountain Growler
Orbea Laufey
These Hardtails don’t come with 2.6 tires but have modern geo.
GT Zaskar
Vitus Sentier
Kona Honzo
Norco Torrent HT
I wouldn’t buy a 27.5 Hardtail unless I was shorter than about 5’5″ inches and I would still want 2.6 tires and not the wider Plus tires. The Salsa Timberjack/Rangefinder comes with 29×2.6 tires but the geo is a bit old school. However, they are pretty good bikes, if you buy a size-up and then put on a shorter stem.