I was working on my computer and everything was fine. Suddenly no WiFi signal. I noticed that the WiFi signal strength dropped for both 2.4 and 5. 
as an example, I am sitting right next to my router and get a low signal and speed. i distance myself to 1 meter away and no signal at all reaching. Same occurred with other smart devices that use 2.4... all are down. iPhone doesn't even find the WiFi if I don't have my phone right above the router. 

it was working a moment ago - nothing changed at home in terms of moving physical objects next or around the router 

no new devices on the network (even checked using Fing)

I checked that my network channel is on a clean range without any neighbors channel conflicts 

disconnected the router and reconnected 

disconnected isp modem and reconnected 

connected directly via lan cable (limited to 100K due to type-c converter) and got a stable 100k internet connection. 

Router dashboard claims that I'm using the most recent firmware (and did not update recently) 

did not change any other router settings rece