I see some misconceptions.
Idle temps are mostly representative of airflow in the case and your ambient room temp. It's physically impossible to cool a cpu below ambient by mechanical means, which cpu coolers are, you'd need a chemical process such as LN2, peltier or phase change setup. So if the ambient in your room is 25°C, and your case has pretty dismal airflow, you can expect idle temps to be from @ 32°C upto @ 50°C. And that's going to apply to any cpu cooler, no matter if stock or the largest Noctua NH-D15 twin tower. Loads on the cpu also add to that, if the pc is running minimal processes, @ 5% load, that's idle. If it's running background apps etc that'll move up to @ 20-25% load, which increases temps. Just running a...