Hi @julesmoretti. Did you see the comment in the GitHub issue you linked?:
https://github.com/firmata/arduino/issues/506#issuecomment-1678656982
Support for the Uno R4 has been added to ConfigurableFirmata.
So I think the best solution is for you to use the "ConfigurableFirmata" library instead of the "Firmata" library. You can install the ConfigurableFirmata library via the Arduino IDE Library Manager (the library has support for UNO R4 WiFi starting from version 3.2.0). After installing the library, you'll find an example sketch that demonstrates the library's usage at File > Examples > ConfigurableFirmata > ConfigurableFirmata in Arduino IDE.