Thanks genpfault and Andreas Wenzel, you guys helped me find out what was going wrong.

So after a bit of tinkering, what do you know? Turns out homebrew installed SDL3 but never actually linked it. After a bit of tinkering in my SDL3 directory, I finally was able to recompile my main.c file without it complaining about a 3rd argument being required.

So uhh... thanks to everyone that helped! And also to anyone that asked me questions about how I compiled/asked for an example, now I can ask questions better.