arduino-audio-tools VS esp32_fmdevkit

Have you found Phil's audio tools for Arduino, they work great on ESP32. https://github.com/pschatzmann/arduino-audio-tools

I use an ESP32-A1S board for that. I use this project https://github.com/pschatzmann/arduino-audio-tools/ and the platformIO vscode plugins.

Have a look at this example to see how easy using that library is :

Check out arduino-audio-tools and other libraries it can make use of, such as ESP32-A2DP. It's tailored towards ESP32 devices, but also supports the RP2040 and others.

The ESP32-A1S is a fun toy to program with that lib https://github.com/pschatzmann/arduino-audio-tools on that cheap kit: https://docs.ai-thinker.com/en/esp32-audio-kit

I have already successfully generated a fairly good 40khz sine wave with the internal DAC using this library: https://github.com/pschatzmann/arduino-audio-tools. I have also played an uploaded MP3 file, but I cannot figure out how to implement FM specifically to modulate the two waves together.

The PCM5102A does a great job. You can get modules for a few dollars, and can even get hat specifically designed for the RP2040. I've got one to work with an ESP32 with the Arduino Audio Tools library. Andreas Spiess has a great video on the subject.

Been wanting to do this myself a good source for this is this linkhttps://github.com/pschatzmann/arduino-audio-tools

Normally I’d recommend one of my YouTube videos :) - but actually this guy has done an amazing job: https://github.com/pschatzmann/arduino-audio-tools

I got it to play both MP3 and WAV files using ESP-audioI2S and arduino-audio-tools, though only single files. AAT uses player.copy() and the other uses audio.loop(), both can call files by name but only once, as far as I can tell.

https://github.com/pschatzmann/arduino-audio-tools and you can program it with arduino

Not exactly what you're looking for, but seems closely related. See if this helps you.

Another option is looking at existing hobby-grade solutions doing a similar thing - https://github.com/dragon-engineer/esp32_fmdevkit seems to be aiming in the direction of your approach, but doesn't have great documentation on the hardware side right out of the gate.