I contacted the support team and I will receive a separate router for gaming, apart from the Horizon that will remain for TV.
I also was notified that there is an option for the “standby power usage” in the Horizon menu (settings - horizon box) that has to be set up as “high”, but the most safest option was to separate the TV from the gaming functions.
(See the manual, http://www.upc-cablecom.ch/content/dam/www-upc-cablecom-ch/Support/manuals/en/hrz/upc-horizon-user-manual.pdf, page 55).
I guess that how to set it up will be clarified on the received router, or if not, will call the support hotline.
Thanks for the quick turnaround and response.