So I took the emulation plunge and bought a Raspberry Pi 4B 4 GB ram with a pre-installed retropie setup, thinking it was going to be fairly plug and play and easy to use. Big mistake. I've already spent too much time troubleshooting why some controllers don't work right, why something is too slow, why something crashes. Makes me feel better about having a cartridge collection that is too big. Someone tell me how I got dreamcast to run full speed and well on this thing and not atomiswave or.... NES!!!
My best advice, use an xbox one controller (the newer ones) and make sure it's updated in Win10. There's a command that you need to type to make it actually work. It works great once you actually get it going, for real. I have no idea why the idiots at retropie or the people who make the images don't make this command already 'done' to make things easier.
It's completely stupid but whatever. Use this video as a guide.
https://youtu.be/lF7ZFnw_PR0
There should be a string of commands in the "more info" section under the vid if you're using a pc. There's a long command there that starts with "sudo nano" and ends with something like ERTM. You have to run that command to turn off... Whatever stupid thing is preventing the bluetooth from actually connecting.
First you have to REMOVE the controller from the connected bluetooth devices. Then run that command, reboot, then try connecting the controller again. Then it should work great.
ETA Primes vid (I'm pretty sure I linked the right one) should help out.
Edit: here's a link to what you need to do to turn off ERTM.
https://techwiztime.com/guide/retropie-xbox-one-controller/