I found a way to circumvent this.
Go to the applications foldes and find the epic launcher.
Right click → Show Package Contents.
Go to Contents → MacOS and run/open EpicGamesLauncher-Mac-Shipping
It will start and it will update allowing you to use Unreal Engine.
(I will add if the launcher works upon close after the install of the latest engine)
Edit: The launcher does not work after close (osx says it is damaged and should be sent to trash) but if you repeat the process stated at the beginning it will start again.