Everyone I know has about 20lb road bike with pedals on them etc.. and that's carbon frame wheels. I think the 15lbs you read about probably cost over 10k.

If your hills are over 10% and several miles long I think you should upgrade or switch to hills closer to 5 to 7% until you can afford to upgrade. I can't imagine doing 12% grade hill with 36 front and 28 rear gears. Especially if you are just starting out.

I switched to a gravel bike with two wheel sets. The gravel bike has lower gears which makes the hills less painful. 32 front 32 rear.