@lesniki45 

Personally, I would not worry too much about this!

2.4ghz will saturate with even the slightest load on it, its a common issue with the lack of bandwidth on that frequency (its massively congested).  My controller for example reads RED on the 2.4  24/7/365 and it still works ok.  

In short the 2.4 is such a small channel width that in the real world even the smallest traffic will saturate it, its almost expected to be honest.  It will likely still work OK for you, just reads bad!

In answer to your query why it happens when no-one is there.. depending on how you have setup your LAN, it could be just background traffic being sent accross the WiFi.  Even with no one connected you will still get a level of background noise from the LAN going accross.

However.. your home router.. being a router.. will stop a lot of this small traffic going over the WiFi.   But it shouldnt really make any performance difference tbh

  @lesniki45 forget about it, 2.4ghz frecuency is crowded beyond belief and there may be tons of reasons it is overloaded, it is not just legacy wifi devices..literally every single old wireless device will take a bite on it including baby monitors, cordless land phones, sensors..whatever.. it is just barely usable and the reason everything was moved to 5ghz.

  @crrodriguez  @Philbert

Thank you!I will consistently switch to 5 Ghz.

In any case, the problem was in the new switches that are not connected to the general monitoring, in the new office that reset their settings to factory settings due to unstable electricity and created storms and conflicts.

I hope my mistakes will be useful to someone