A Trail bike is probably your best bet. These bikes are designed to be the most versatile option in the mountain bike lineup, balancing climbing efficiency with confident descending capability. They handle everything from flowing singletrack to chunky descents without feeling out of their element on either end.
Trail bikes shine for general trail riding, all-day epics, and varied terrain where you're climbing and descending roughly equally. The geometry is neutral enough to feel comfortable on long rides but still capable when the trail gets rowdy. Most riders—especially those who explore different trail systems—will find a Trail bike covers 80-90% of what they want to do.
The main reason to look beyond a Trail bike is if you have a very specific focus. If you're racing or obsessed with Strava times, an XC bike will feel faster on climbs. If you spend most of your time on steep, technical descents or at bike parks, an Enduro bike adds capability there. But for one bike that does it all well, Trail is hard to beat.