I know what you're thinking: it's Gwent and I don't like card games. But trust me on this one, because Thronebreaker is really, really good.
Where Thronebreaker succeeds is in taking the basis of Gwent and reconstructing it into a full adventure video game experience, providing a framework for Gwent to operate alongside more traditional role playing and adventuring content. There are several maps to explore, each interacted with via a classic isometric perspective, point-and-clicking through locations to unravel secrets, meet NPCs, and progress the story. Context is always given, the game rich with interactive dialogue and visual set pieces to draw you into the story. Meanwhile Gwent itself is used as a backbone for puzzle solving and combat.
The magic is in how inventive the use of Gwent is. It's not as simple as building a deck and having every match play out the same way, but instead battles often having contextual requirements, gimmicks, and scripted sequences that give them context to their place in the world and narrative. Stories aren't just told outside of battle, but during battles, cards and sequences shifting as the narrative does. It erodes all sterility from the risk of repetition and makes every battle feel fresh, engaging, and driven by narrative.
And rounding out the whole package is CDPR's trademark production standards, breadth of content, and attention to detail. What could have easily been a phoned in effort is everything but. It has a unique soundtrack on par with The Witcher 3's work, dialogue is well written and performed, choices with far-reaching consequences ripple throughout missions, there's a ton of optional side content and stuff to discover, and the enormity of the main quest makes it more than worth the relatively cheap price of admission. I also thought it looked super gorgeous.
As far as I'm aware it didn't perform all that well. And I get why; no matter the production standards a Gwent specific game was only ever going to appease a minority. But if you enjoyed Gwent in any way from The Witcher 3, and want more "The Witcher" stuff, I cannot recommend Thronebreaker enough. Give it a chance because it's fantastic.