ok, since you said you're new to game development, maybe you could start by making some pretty minimal and simple games, like platformers, to get used on how to actually make a game. Imo pratice makes perfection, so if you can, try making lots of small projects, to get used to all the things on game development (like coding and arts).
You don't need AAA graphics, as an art style that is good enough only for understand the game already is enough for a while. I would recommend color palletes.
Avoid using AI art (unless you know what are you doing), it usually never is what you want, plus often your own art will end up being better.
Starting a game but getting tired of it is very common, so if you notice you're getting tired of your game, stop trying to add more features and focus on doing the bare minimum your game needs to be playable (often UI screens like a main title, a level select, and a game over are enough, plus 5 levels should be good enough).
Don't spend money on anything game dev (at least not as a beginner), not only because everything you need to make games is free, but also because getting money with your games is pretty challenging.
Do you need tools? i use unity for making games, vs code to make codes (way better than visual studio, lighter, easier to understand), blender if you need to make models, and sites like beepbox to make music (i used beepbox to make the songs of my games, until i started to become an actual music producer lol), jsfxr to sfx sounds (way better than sfxr and bfxr, just saying), ambientcg for public domain textures, and piskel for pixel art. I'm also using more obs studio to record my games after i build them (tho you can record them inside unity by using the package unity recorder), and shotcut to edit the videos. (Note that all the programs i just mentioned are free).