I’m not going to argue against the standalone controllers, UCNC or Acorn as from what I have seen and read they are great options.
I just wanted to add that I’ve been using Mach3 for years and years on an old offline PC using the parallel port into a free breakout board and have not had any issues that I can recall.
I might be making simple parts perhaps, or only running at a hobby pace but I’m pretty happy with it. I made the current CNC machine with it for example.
They used to have a free version with limited gcode (500 lines) to get you going. Having said that it if stopped working I would review my options.