First TREK bike.

This is my first TREK bike (Marlin 8 M/L) bought new from store ($1500.00 cdn). A bit about me I m 45 years old about 5’6” 190lbs with 31.2 inseam. I picked up my bike this last Saturday and been riding just the past four days. I travel about 9 km one way that 18km a day. I choose the mountain bike due to conditions on the road (construction, potholes, curbs, etc).one of the first noticeable issues I encounter is the handle bar being so wide makes me wrist roll to the outside causing pain in my wrist even on such a short trip. Number two and this is really bothering me it’s top speed I find my self running out of gears and pedalling on empty. Even though I’m travelling around 22km/h the bike feels like a tank to me. The last one not sure if it’s me because I purchased a bike to big two times m back tire when under and sideways. The tires seem to have no grip on asphalt and concrete. Last one but not as important cause it does have two water bottle holder but you can only fit short bottle in them. My question to the more experienced riders is this did I buy a bike too big for me? Should I have gotten the M? Can I shorten the handle bar? Is there another bike in the TREK line up that would be more suitable for my type of ride? I have a bit of time to exchange any advice would be welcomed.

Thank you

Ps:. The photo shows the bottle holder but I also installed an Apple air tag on it.