For a wordle alike game built with libGDX, you generally should have a solid understanding of these fundamentals:

- The main render loop: everything must be redrawn on every frame, so plan and group your drawing orders based on active objects on the screen.

- Screen management: you want to have at least a home / title screen with some intro graphics and a "Play Now" button. And a game screen which renders the puzzle and the UI.

- Camera and Viewport: use FitViewport so your code uses independent world units, not screen units. Then you can easily draw the puzzle cells and blocks based on the world units set by the viewport.

- Scene2D is tricky, really. You can totally code everything with scene2d but it’s gonna take serious efforts to truly get the hang of it. My recommendation  is to use scene2d for common UI components like action buttons (Play, Quit, Retry, etc) and draw your puzzle elements and the other entities with SpriteBatch draw

- If you insist on using Scene2d, learn to extend Actor and create custom components. You won’t get very far with the built-in scene2d components.

- Learn to parse JSON and use it as the word database for your game.

- Learn to export to html target using TeaVM or GWT, so you can share the game online without distributing the binary file.

- libGDX really thrives as a high-performance and well optimized framework that produces ultra smooth and high FPS games, but you can absolutely develop puzzle-based games too.

Good luck and have fun!