Congrats on finding a bike you like. While you can upgrade the crankset, that would not be my priority unless the current one is causing issues or you want to change the gearing.

First, I would look at some brake levers where both the lever and the body are actually made of metal. Cheap plastic levers are prone to snapping in two, and also make your brakes weaker. You want levers intended for long pull brakes.

Second, I would overhaul the bearings in the hubs, bottom bracket, and headset. While these are low quality, just like every other part on the bike, their lives can be extended by cleaning everything out, getting fresh grease in there, and adjusting them as well as you can. Bearings on a bike like this from the factory tend to be poorly greased and adjusted too tight.