@SmashedTransistors, the problem may not be as essential as you describe, I know Arduino boards and clones all work fine with serial options, so does the teensey.
And there are also many other boards (NON STM) that designate their IDE setup to Arduino IDE, in most cases I would expect these are safe too, but you will need to read the details for the board to confirm this.
One thing is for sure, communicating with an Arduino Due board to the Axo via UART to midi which works very well because this is my setup. The Arduino due has 4 x uarts, SPI and I2C, but I do not use the I2C. SPI is used for an SD card, and I have plans to use more Uarts.
If you are adventurous, try something different like an STM32f103 or Nucleo board, if you want something that I know works, stick with Arduino or Teensey or similar, with Arduino or Teensey, there are plenty of shield and modules that can be added with a lot of work already done for them to work. Just check through the details and ensure you know what you need.