We spend months upon months educating ourselves. Reading, listening, discussing.
Because why not. Knowing stuff you're working with never hurts.
Hard to explain in layman's terms but it's a thing that makes your graphics card run a game in a lower resolution with addition of some magic so you spend way less resources and still have about 98 to 100 percent of image quality saved. This is mostly used to gain more FPS but some gamers enable it at 100% resolution to improve visuals, and some only enable it for energy saving purposes.
These are tiny processors that crunch numbers. They are exactly what makes your 3D software dance. What makes them unique and called CUDA is instructions that make the whole process more efficient. AMD and Intel GPUs don't have CUDA cores. For more detailed explanation:
https://en.wikipedia.org/wiki/CUDA or just google it and read articles on that.
Your i5-12600K is nothing wrong. You just need a GPU to produce magic. The most recent GPUs are RTX 3000 series and RTX 4000 series. Upcoming 5000 series won't come any time soon if we talk sub 500 dollar SKUs. 4060 is power efficient and can do a lot.