The bike is what it is. While some would rush to condemn it, I will note that a big-box bike like this is worlds away superior to big-box bikes of 30 or 40 years ago, and with some basic maintenance should work just fine.

There really IS a point of diminishing returns. Maybe my story will illustrate it. When I was a kid in 1973, my father bought me my first 10-speed bike. Fortunately for me, the first bike, a basic welded American BMA/6 thing with Ashtabula cranks and Shimano Eagle derailleurs was actually missing some vital parts, so Dad returned it and came home with a West German-built "Brownie," probably built by Kalkhoff. It was one of the many bike sourced from makers world-wide to meet the demand of the Great Bike Boom of the early 70s. It had all the hallmarks of bottom rung European 10-speed - steel rims with 3-piece hub shells laced with galvanized spokes to steel rims, gas-pipe tubing that was at least lugged, but was squished flat at the dropouts and crudely attached to stamped ends, a steel cottered crank, plastic Simplex derailleurs, Altenberger Synchron sidepulls and a nasty hard a$$-hatchet plastic saddle. I actually did upgrade some things on it, and learned several lessons the hard way. 1. DIY repainting a bike rather than cleaning it and living with the stock paint job is a bad idea and looks like home-made hell. 2. Replacing broken Simplex derailleurs with budget SunTour alloy units makes sense and was cheap, easy and a genuine upgrade - replacing the Altenberger brakes with expensive Italian Universal mod. 61 sidepulls that cost almost as much as the bike sold for new was a bad idea. 3. The difference between the $50 big-box bike vs. the $150 bike shop bike that replaced it two years later was far more than the 3:1 cost ratio.

Were I in your shoes, I would ride the bike you have now and (apart from saddle and pedals!) would only REPLACE stuff if it breaks or wears out. I would NOT upgrade anything, unless it was an incidental upgrade to replace broken or worn-out stuff. I would also ride the snot out of the bike and make notes on what I wanted next. Finally, I would learn all I could about how to service and repair bikes.

I am NOT enamored of new bikes, and for the riding you're doing, I would tell you to figure out what size and dimensions of bike fit YOU, then start keeping an eye out for a high-quality older mountain bike at a bargain price. Ride what you have while you do so. Sooner or later a deal will come along. As I write this I have a 2007 or so Giant Yukon 24-speed with disc brakes and a front shock that I paid $20, then another $4 for a rear brake cable. Once I fixed the rear brake, I pumped up the tires, lubed the chain - and it runs beautifully. Pity it's too big for me! I just had a nice older used Cannondale offered to me for $25. If you can use tools and watch YouTube videos you will get a much better ride experience out of an older bike shop quality bike than you can get from a big box machine.