arduino-esp8266fs-plugin VS ESP8266Audio

I use the wifimanager library imported into arduino ide, it makes the device act as a wifi access point and then you put the credentials in there. you can also handle how reconnects and things work with the code. You can also use this https://github.com/esp8266/arduino-esp8266fs-plugin to push a SPIFFS image which can be accessed from the code after uploaded

You mention uploading the sketch, but don't say anything about uploading the filesystem. So, I'm guessing you didn't. The easiest way is to use the Arduino ESP8266 filesystem uploader.

Having an issue here using the ESP8266 Audio library (found here).

The Arduino sketch that works for me reads the data out of PROGMEM. When I use that same raw data in ESPhome, it crashes my ESP too. Would there be a way to play from PROGMEM in ESPhome too? Other ways in the library are a function or streaming, but that doesn't fit my use case unfortunately.

If you're getting started, the ESP8266Audio library makes it easy to play audio with the Arduino toolchain. For more advanced use cases, Espressif's own ESP-ADF has a lot of useful features and examples.

Not sure where you got that. According to the ESP8266Audio documentation, the default GPIOs are 2, 15, and 3. You're trying to change 15 to 13.

ESP8266Audio is really fun and easy to use

The ESP32 might suffice for that then, depending on what you consider to be basic applications. It certainly has wifi and bluetooth functionality and you can do audio with an extra chip or an interesting workaround. The ESP32-A1S module even has the necessary chip integrated but you'll likely need to roll a custom PCB for it.

I am simply using the sample code from here. https://github.com/earlephilhower/ESP8266Audio