Update for those who are on mac intel and above methods worked and then stopped working.
Every time I play on either my mac mini or macbook with a controller I have to unpair the controller, add it, and check that the libSDL2.dylib is in place. After a few times, the controller didn't work for stardew anymore even though libSDL2.dylib was in place. The file would randomly be removed every day or so and now I saw a new file (maybe per an update?) that was called libSDL2-2.0.0.dylib . If you download the above mentioned file (and keep it on hand just in case!) you can rename libSDL2.dylib to libSDL2-2.0.0.dylib and replace that file and your controller should start working again.
To recap the long steam thread, mac changed from kext files for controller input to a new framework called driverkit. Valve didnt make an update to driverkit so thats why we have issues. If you're like me, going to that steam thread and running kmutil (which has also been updated since) you may find that you dont have a SteamInput.kext in the /Library/Extensions folder. I haven't found a way to get this file by itself. Even though a kext file is a security issue, I'm still looking for that freestanding file. If you're reading this and found you have SteamInput.kext in your library extensions folder, could you perhaps share it with those who do not have it?
I hope this helps someone else as this seems to be an ongoing and evolving issues. Regarding libSDL2.dylib, I expect to check it for naming updates every day until it stops getting deleted.