For transmitting infrared, the used microcontroller does not matter; it is a well-documented and super straightforward task. The ESP8266 has the advantage of WiFi and lots of libraries available to make building something with a web interface super easy.
If you are into STM32, there is an ideal board with S/PDIF in (including subchannel-data) that I would like to make great use of as an ITTS box replacement, but I am apparently not competent enough to get the S/PDIF input to work: S/PDIF input to USB, is ITTS in I2S? - #5 by Max If you can help, please follow up in that thread, I would even send you one.