I like "South Park," the show, well enough. I saw the movie in theaters a million years ago. I played the first game (for work, but I enjoyed it!).
If none of this applies to you, or you outright dislike "South Park," I doubt very much that you'll suddenly turn around on the franchise after playing "The Fractured But Whole." It's essentially a very long episode of "South Park," the show, with a lot of interactivity. You explore the town of South Park, talk to people, collect stuff, and fight enemies. There's a lot of room to explore as you wish, as well as a main progression path to stay on if you'd prefer something a bit more straightforward.
And all that stuff is good! But it's the "South Park" writing and voice acting and storytelling that makes "The Fractured But Whole" something unique.
In that same vein, "The Fractured But Whole" is an old-school RPG with modern graphics. Combat is turn-based, meaning that combat is literally on a turn-by-turn basis — it's a tactical system instead of a real-time system.
If this all sounds like gibberish to you, you probably don't want to play "South Park: The Fractured But Whole." That said: "The Fractured But Whole" is a very easy introduction to the world of RPGs. If you're looking for an access point to role-playing games, this is it.