Brightness buttons on the laptop no longer work (Windows 10, Acer)?

I have an Acer Spin 3 with Windows 10. My brightness buttons have stopped working for a few days. In the settings I can change the brightness, but no longer using the two buttons. Volume etc but everything still works. I restarted my laptop and updated it several times, but it didn't work. Does anyone know?

Is either dirty or defective, if possible carefully remove the buttons and see if nothing is stuck on.

It's not because the key works when I press it with Fn

Then that was probably accidentally deactivated somewhere how does it look in the pc with the control panel? Or has some new program been downloaded? Is something strangely active in the background? (can be checked via task manager)

Well, at first glance I don't notice anything unusual

Well now I really have nothing to say about the PC, I would say check the brightness settings in the control panel, maybe there's something to be found.