Selecting a cable provider (Single Sign-on) is not supported on macOS. The purpose of that setting is to ease the many sign-in requests by various apps, and these apps do not exist on macOS.
Sign in with your TV provider on your iPhone, iPad, or iPod touch - Apple Support
Use your pay TV or cable provider with your Apple TV box - Apple Support
TV providers that let you sign in on your iPhone, iPad, or Apple TV box - Apple Support
The various networks may have web portals that you can make use of on macOS in a web browser.
The Apple TV app is not Apple TV+. Apple TV+ is a small part (one of the channels) of the Apple TV app, and completely unrelated to your TV provider.
The Apple TV app may provide access to select premium channels, but these require their own subscription, which is not exchangeable with any subscription started outside of the Apple TV app, despite the familiar channel names. Best to make a choice for one or the other: Always watch these premium channels in the Apple TV app, or always watch them outside the Apple TV app.
Apple TV Channels FAQ: Services, pricing, availability, and everything else you need to know - Macworld
Subscribe to Apple TV channels in the Apple TV app - Apple Support