I also use Niri. Previously I basically used maximimized windows on dual monitors. But I really liked the idea of switching to one ultrawide display. Maximized windows wouldn’t work well in that setup. Tiling hadn’t really worked for me because you end up with a screen full of awkwardly skinny or short windows, or windows hidden away in tabs. I also didn’t like the idea of managing floating windows with… a mouse.
So I looked for a better option. I found PaperWM, and I loved it! Exactly what I needed! But it has a number of quirks, being an extension that entirely reworks Gnome’s window management. For a long time I wished for a native scrolling wm. And then Niri came along! And it’s so polished!
If you’re getting started with programming the first resource I point people to is Scratch. It’s the easiest way to get started, and teaches programming concepts with guide-rails. I recommend looking at a game someone else has made on the Scratch website, and “remixing” it to tinker, and understand how it works.
When you hit the limitations of Scratch, and want more I agree with other commenters that Godot or LÖVE are good next steps.