So i was trying to mess around with the buzzer on the Nextion Expansion Board and noticed when I'm using pwmf=0 (by accident) the pwm output is not working anymore. I need to reset the Nextion to fix this.
I apologize for the long delay, and that no one responded until now.
Try creating an HMI with pwmf=1000 command in the page Preinitialization Event.
Compile and load onto the Nextion device by the microSD method
(clean formatted microSD card, only file on microSD is your tft file)
Then try your original project again
Please report if this method has solved the issue