npm start not working because of Webpack mismatch - node.js

Question

I recently copied over a React frontend into the assets folder of my Phoenix backend and also added Webpack.
When I run npm start, I get this error, even when I remove node modules folder and package-lock.json file and run npm install, I get the error again when running npm start.
The react-scripts package provided by Create React App requires a dependency:
"webpack": "4.19.1"
Don't try to install it manually: your package manager does it automatically.
However, a different version of webpack was detected higher up in the tree:
/Users/danale/Projects/node_modules/webpack (version: 4.29.0)
The error sounds straightforward except that I did a npm ls webpack and I am using the version the error says I should be using:
└─┬ react-scripts#2.0.5
└── webpack#4.19.1
Please point me in the direction I should be looking.
Here is my package.json file:
{
"name": "myproject",
"version": "0.1.0",
"private": true,
"dependencies": {
"#material-ui/core": "^3.2.1",
"#material-ui/icons": "^3.0.1",
"apollo-boost": "^0.1.23",
"apollo-cache-inmemory": "^1.4.0",
"apollo-link-context": "^1.0.12",
"apollo-link-http": "^1.5.9",
"axios": "^0.18.0",
"classnames": "^2.2.6",
"eslint-config-airbnb": "^17.1.0",
"graphql": "^14.0.2",
"graphql-tag": "^2.10.0",
"jest-dom": "^2.1.0",
"moment": "^2.22.2",
"phoenix": "^1.3.4",
"prop-types": "^15.6.2",
"react": "^16.5.2",
"react-apollo": "^2.3.3",
"react-beautiful-dnd": "^9.0.2",
"react-dom": "^16.5.2",
"react-redux": "^5.0.7",
"react-router": "^4.3.1",
"react-router-dom": "^4.3.1",
"react-scripts": "2.0.5",
"react-testing-library": "^5.2.0",
"redux": "^4.0.1",
"redux-saga": "^0.16.2"
},
"scripts": {
"start": "react-scripts start",
"build": "react-scripts build",
"test": "react-scripts test",
"eject": "react-scripts eject"
},