Error: [BABEL] /app/src/index.js: Cannot find module '@babel/plugin-proposal-private-property-in-object

Question

After a successful build using npm run build and then a successful Heroku deployment, I get this runtime error in the browser

I've followed instructions from this GitHub issue and placed the proper version in both my "dependencies" and "devDependencies" sections of my package.json file.

{
  "name": "workout-app",
  "version": "0.1.0",
  "private": true,
  "dependencies": {
    "@babel/plugin-proposal-private-property-in-object": "^7.21.11",
    "@babel/preset-env": "^7.22.7",
    "@babel/core": "^7.22.8",
    "@emotion/react": "^11.11.1",
    "@emotion/styled": "^11.11.0",
    "@mui/icons-material": "^5.11.16",
    "@mui/material": "^5.13.6",
    "@testing-library/jest-dom": "^5.16.5",
    "@testing-library/react": "^13.4.0",
    "@testing-library/user-event": "^13.5.0",
    "cors": "^2.8.5",
    "express": "^4.18.2",
    "express-validator": "^7.0.1",
    "mongodb": "^5.6.0",
    "react": "^18.2.0",
    "react-dom": "^18.2.0",
    "react-router": "^6.14.0",
    "react-router-dom": "^6.14.0",
    "react-scripts": "5.0.1",
    "web-vitals": "^2.1.4"
  },
  "scripts": {
    "start": "react-scripts start",
    "build": "react-scripts build",
    "test": "react-scripts test",
    "eject": "react-scripts eject"
  },
  "eslintConfig": {
    "extends": [
      "react-app",
      "react-app/jest"
    ]
  },
  "browserslist": {
    "production": [
      ">0.2%",
      "not dead",
      "not op_mini all"
    ],
    "development": [
      "last 1 chrome version",
      "last 1 firefox version",
      "last 1 safari version"
    ]
  },
  "devDependencies": {
    "@babel/core": "^7.22.8",
    "@babel/plugin-proposal-private-property-in-object": "^7.21.11",
    "@babel/preset-env": "^7.22.7",
    "@babel/preset-react": "^7.22.5",
    "babel-loader": "^9.1.3"
  }
}

Thanks to anyone willing to help! I'm still learning and would greatly appreciate any feedback:)

I've created an issue for it in GitHub as well: https://github.com/kyle-mucerino/workout-app/issues/1#issue-1797407298