You cant do anything with the finished firmware.bin file. That is like looking at a cake and wanting to change it from chocolate to banana. You just can't do it, you have to make a new cake.
You need the firmware source code and Configuration files. You make the changes you want to the config files or if required the source. You then compile the source into a new firmware.
The standard tools are a code text editor vscode [
code.visualstudio.com]
From in that program you install the platformio plugin
Many also install the Auto build Marlin plugin
That is all you need all other requirements are automatically downloaded and installed by platformio as needed when you build the firmware
