This might be a hot take but I think the best controllers are from Xbox. The new PS5 controller is amazing but I go back to Xbox for everything non Playstation. When I saw a couple videos showing bluetooth capabilities for the Nintendo 64 and Gamecube, I jumped on them immediately.
The Nintendo 64 mod was more fun in my opinion because you build the dongle yourself for relatively cheap. I believe the total came up to around $45 Canadian for both the ESP32 board and controller extension cables. If you have basic soldering skills I recommend trying this mod for yourself.
Achieving bluetooth on the Gamecube requires replacing the entire controller port board with a custom one from Laser Bear Industries. It sounds scary but it a solderless mod and fairly simple to install once you make sense of all the cables.
All 4 ports can now be connected through bluetooth! Cool bonus of the mod is the ports light up blue when they’re paired with a controller and the top orange LED changes color while pairing new controllers.