Acer Nitro 5 AN517-51 cooling itself when it's not needed

Hi!

I recently bought this (new) laptop, updated BIOS to its latest version (May 2020), and still have a question about its heating and cooling.

According to NitroSense, both fans are spinning at about 4,4k RPM when CPU's temp is 38C, and GPU is 0 (?) or when it's not under load. I saw an RPM chart somewhere on this forum, saying that when the temps are lower than 40C the fans should not be spinning. Even when the temps are about 40-45C they still spinning at about 4k RPM. A "CoolBoost" thing in the NitroSense helps to solve the issue temporarily. Sometime after the fans again start spinning when they do not need to.

Coolboost: https://i.imgur.com/oRnFwei.png
No Coolboost: https://i.imgur.com/2OmcSMw.png

Moreover, if I set the fans to "Custom" and just disable them, they start spinning like 5 mins after it, even though I don't play any games, just doing stuff in Word and Chrome.
Custom "disabled" fans: https://i.imgur.com/Dk6QO2g.png

I tried downloading NoteBook FanControl (NBFC), and the laptop just won't listen to the settings I set in the app. I set "Disabled", fans starting to spin whenever they want. I set "Enabled" and set it at 30% - they spin at 70%. https://i.imgur.com/crPU9ew.png

What might be wrong with the temps/fans and is it possible to fix it? Thanks!

Win 10 Pro, Licensed, Build 18363, BIOS updated, Nvidia drivers are updated.