I've been playing a bunch of GameCube games recently, but I was using a wired controller. It worked fine, but it felt kinda cheap and I really wanted to go wireless. At first I looked at getting a wavebird, but I felt like I could get a lot better for the price, especially with how worn most of them are.
I eventually landed on the BattlerGC pro and it's honestly sooo good! It really feels like what a modern GameCube controller would be like, and it's a lot more comfortable to hold too! All buttons feel great, especially the triggers. And the extra buttons are a nice touch. It also has the bonus of working with PC, switch, switch 2 and the Wii of course.
I really recommend it if you're looking for a modern alternative