Originally Posted by BoraxKid

That sounds like a perfectly reasonable budget for a road bike that should be step (or two) above entry-level. When I was bike shopping a few months ago, the difference between a $1500 vs $2500 road bike was the frame and wheels in almost all cases. The more expensive bike should have a carbon frame and will probably have 105 components with disc brakes, and wheels that are tubeless ready. The less expensive bike will likely be an aluminum frame with rim brake wheels, although some will have disc brakes. Since your aim is to go fast, buy the carbon frame bike, since it will be more aerodynamic (and slightly lighter).

If it matters to you, all of the road bikes I found in the $2000-$3000 range only came with a compact (50/34) crankset, except for Canyon. If you think you need bigger gears, you will likely have to pay for bigger chainrings at some point.

Edit: I missed the part where you said you were planning to buy used. Don't do that just yet. Look online and see what is available new; there will be plenty of options for your price range. Specialized, Canyon, Trek, Cannondale, and Giant all have new, 105-equipped carbon road bikes in the $2500-$3000 range.