Hi @ruicoito,
Following that option lets you set the NVIDIA card as the primary one for every purpose. It usually requires a reboot after enabling the PRIME support for having everything offloaded to the discrete GPU and after disabling the PRIME support for having everything be on the integrated one. There will be no visible PRIME option to interactively switch between the usage of two cards when the solution mentioned at [Solution] Easy PRIME setup using NVIDIA Auto Installer for Fedora is used.
Where did you install envycontrol from and what are the steps that you used to configure the said PRIME setup, which (like I mentioned before) does not happen instantly and will always require a reboot?