I have an very noisy fan on my Lab top and ask Fedora if I can lower the noise by using an application or do other technical adjustments. I know cleaning or changing the fan also could be an hardware option.
The only choice in the moment to rid of a noisy fan by the Asus machine I using could be starting another topic about Fan control. I know there is a app for iMac where you can raise or lower the cycles. But very important is not to overheat and burn the processor.
If issue is that your processor getting hot that is why fan makes noise and you artificially slow down that fan it can lead to bad performance and thermal slowdown and may underperform your cpu.
And also monitor the applications if something is taking more than usual amount of resources like cpu. You can kill that and see if issue resolves and give us feedback.
Watch the noise you are hearing is maybe due to overheating you can monitor the temperature of your cpu and if you think it is getting hot so your device fan gets rammed up like crazy. As your laptop was not sounding that before so
Sometimes the processor thermal compound gets dried up so it can’t transfer the heat efficiently it may cause this issue
Sometimes processor fan gets clogged and makes noise
If you have that much technical knowledge and you are comfortable with this much details then repasteing with a good thermal compound can solve this issue. i have done this before 2years ago and it is hard really hard.
**#**Caution you may destroy your device if not done correctly.