hi, i I've figured out this issue that i also experienced. my laptop fan used to be making less sound but after updating windows to 1903 version it occurred and it's kinda frustrating me cause it's noisy.
I've done so many way to fix this issue but nothing worked. i don't get it but when i turn off the transparency effect in settings, the fan stop making loud sound and spinning as it used to be. i kinda feel weird about this because transparency effect makes your windows appearance looks great.
i hope this can also help you all to fix this issue
and i hope Microsoft can fix this issue asap because this is quite annoying