Here is a list of things you can do to troubleshoot the fan noise:
Ensure your laptop is well ventilated and clear of any obstructions.
Make sure your CPU and GPU temperatures are not too high.
Check your laptop vents for any blockages.
If you feel comfortable to do so, clean out the fan of your laptop.
Try running a dedicated cooling software to reduce temperatures.
Run a thorough virus scan to make sure that no processes are running in the background.
