Thank you for your answer. I did what you instruct and i got a warning from your biased tool that i do not have wifi optimized. I absolutely don’t think this is the reason why sometimes, specially at night my Internet speed is reduced dramatically.
So i dedided to get it optimized anyways and tweak in with proper channels and use the 5GHz for most speed, etc.
And i found out that my router or rather your UPC router is transmitting two additional pair of Wifi broadcasts without my permission. Particulary the non hidden “UPC Wi-Free” SSID. You can see in the picture the top 4 sharing same MAC address for each type of Wifi broadcast.

If this is not the reason why i have seldom Slow Internet Speed, its disturbing and i don’t like it nonetheless!
I searched in your UPC website how i could deactivate this UPC Free WIFI and it says
(https://www.upc.ch/en/support/internet/wi-free/#:~:text=How%20can%20I%20deactivate%20Wi,log%20out%20of%20Wi%2DFree. ) that i can do that in My UPC. I checked and its deactivated. If its deactivate how come i am broadcasting it?
I want to deactivate this Wifi and your help wil be appreciated!
Thank you.