I'm running RetroPie on a Debian laptop and I'm able to map all the buttons of my 8BitDo Pro 2 controller; no issues at all. I was also able to connect and configure an Xbox 360 controller just fine.

You might want to try getting help on the RetroPie forums if you don't get any luck here.

First of all, doesn't Navidrome have authentication? So, I don't see why exposing it to the public is a problem.

Second, some reverse proxies support basic auth. This way, you can password-protect some services and is useful if the service does not have its own authentication. Here as an example snippet for Caddy:

example.com {
	basic_auth {
		# Username "Bob", password "hiccup"
		Bob $2a$14$Zkx19XLiW6VYouLHR5NmfOFU0z2GTNmpkT/5qqR7hx4IjWJPDhjvG
	}
	reverse_proxy myservice:8000
}

You'll have to look up the docs for other reverse proxies.

If you need S3-compliant storage for testing and development, you can use an S3 mock server. I've tried the following for use in web development and CI environments, they are lightweight and configurable:

• Adobe S3Mock
• s3ninja

There is also Localstack. I found this one to be a bit more complex than the ones above and ended up not sticking with it.