I've tried every "solution" on the internet and no matter what I can't get this to work. What am I missing?

node -v: v12.16.1
npm -v: 6.13.4

package.json:

{
  "name": "collaboratemd.com",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "build": "gulp sass"
  },
  "devDependencies": {
    "gulp": "^4",
    "gulp-sass": "^3.1.0",
    "gulp-sourcemaps": "^2.6.0"
  }
}

I've tried rebuilding node-sass, I've tried sudo npm install, I've tried file permissions, I've tried various versions of NPM, Node, and Gulp, nothing. Please help this is killing me!!!