First things first, check out the condition of the carbon fiber parts. The headset top cap looks like it could be a compression plug, which would indicate the fork has a carbon steerer tube. If the previous owner wasn't careful and overtightened the stem bolts, they may have cracked the steerer tube, making the bike unsafe to ride until the fork is replaced. Properly tightening the stem bolts is done with a torque wrench. If you don't have a torque wrench, get one, or bring the bike to a shop to have the steerer tube inspected and to have the headset readjusted afterwards. If it turns out your steerer tube is aluminum instead, then it is safe to raise the bars a bit by putting all of the spacers beneath the stem. I'd also check the wheels and the rest of the fork for cracks.

Assuming nothing is cracked, you have a decent collection of parts attached to a mediocre frame. Upgrading it or selling it to get something else both seem like valid options. Another route would be to swap the bars and/or stem, spend some time riding the bike, get the fit dialed in, learn what you do and don't like about it, then decide if you want to invest more in the bike, or move on to something else. The wheels are nice, you could find another road bike that would be compatible with them, swap wheels and brake pads, then sell this one.