Filament end Management... good question that deserves an answer.
Though I’m familiar with Marlin firmware, there is enough similarity that I can minimally comment...
Thus, from my perspective and experience, you should be able to:
Enter into the Firmware Code and set (add) code to respond to button presses, display LCD info... etc
(I have done this on several MKS Marlin-based printers).
This Link may be a good starting point for your Firmware.
https://betrue3d.dk/smoothieware-mks-sb ... and-intro/
Also, if seeing you’re nearing the end of filament, you can:
Count the number of remaining loops on the Filament spool and calculate approx remaining length.
See attached cartoon.
Also, I suspect your printer has some ability to Stop(Pause) if sensing a broken filament. Thus, you can assess what machine does when ‘that’ happens.
Cut the Filament and see what happens. On my machine, it pauses and Extruder moves to front of machine and waits for new filament and a button press to resume.
Also, if Printing via USB, you should be able to use Simplify’s machine control panel to Pause (there’s a Pause Button). Can also learn G/M-Code command to Pause and use Simplify’s Communication field in the Panel to issue the Commands.