@S2art -- do you have any devices connected via an Ethernet cable to the cable-modem? If so, do these devices lose their Internet connection at the same time as your WiFi-using devices (smart-TV, smart-phone, notebook) lose their Internet connection, or do those "hard-wired" devices keep the connection, while only your own WiFi stops?
Do you live in a MURB (Multiple Unit Residential Building), where there are many overlapping WiFi "clouds" that emit from every cable-modem in the MURB, or in a single-family dwelling? It could be "interference" that interrupts your WiFi.
