MobX with React - reactjs

Question

I am new to MobX with React. So wanted to practice a bit. I created a project with Create React App. I have my package.json as
{
"dependencies": {
"#babel/core": "7.6.0",
"#svgr/webpack": "4.3.2",
"#typescript-eslint/eslint-plugin": "^2.2.0",
"#typescript-eslint/parser": "^2.2.0",
"axios": "^0.19.0",
"babel-eslint": "10.0.3",
"babel-jest": "^24.9.0",
"babel-loader": "8.0.6",
"babel-plugin-named-asset-import": "^0.3.4",
"babel-plugin-transform-decorators-legacy": "^1.3.5",
"babel-preset-react-app": "^9.0.2",
"camelcase": "^5.2.0",
"case-sensitive-paths-webpack-plugin": "2.2.0",
"css-loader": "2.1.1",
"dotenv": "6.2.0",
"dotenv-expand": "5.1.0",
"eslint-config-react-app": "^5.0.2",
"eslint-loader": "3.0.2",
"eslint-plugin-flowtype": "3.13.0",
"file-loader": "3.0.1",
"fs-extra": "7.0.1",
"html-webpack-plugin": "4.0.0-beta.5",
"identity-obj-proxy": "3.0.0",
"is-wsl": "^1.1.0",
"jest": "24.9.0",
"jest-environment-jsdom-fourteen": "0.1.0",
"jest-resolve": "24.9.0",
"jest-watch-typeahead": "0.4.0",
"mini-css-extract-plugin": "0.8.0",
"mobx": "^5.15.1",
"mobx-react": "^6.1.4",
"optimize-css-assets-webpack-plugin": "5.0.3",
"pnp-webpack-plugin": "1.5.0",
"postcss-flexbugs-fixes": "4.1.0",
"postcss-loader": "3.0.0",
"postcss-normalize": "7.0.1",
"postcss-preset-env": "6.7.0",
"postcss-safe-parser": "4.0.1",
"prop-types": "^15.7.2",
"react": "^16.11.0",
"react-app-polyfill": "^1.0.4",
"react-dev-utils": "^9.1.0",
"react-dom": "^16.11.0",
"react-redux": "^7.1.3",
"react-router": "^5.0.1",
"react-router-dom": "^5.0.1",
"redux": "^4.0.4",
"resolve": "1.12.0",
"resolve-url-loader": "3.1.0",
"sass-loader": "7.2.0",
"semver": "6.3.0",
"source-map-explorer": "^2.0.1",
"style-loader": "1.0.0",
"terser-webpack-plugin": "1.4.1",
"ts-pnp": "1.1.4",
"url-loader": "2.1.0",
"webpack": "4.41.0",
"webpack-dev-server": "3.2.1",
"webpack-manifest-plugin": "2.1.1",
"workbox-webpack-plugin": "4.3.1"
},
"devDependencies": {
"eslint": "^6.7.2",
"eslint-config-airbnb": "^18.0.1",
"eslint-plugin-import": "^2.18.2",
"eslint-plugin-jsx-a11y": "^6.2.3",
"eslint-plugin-react": "^7.17.0",
"eslint-plugin-react-hooks": "^1.7.0",
"flow-bin": "^0.111.3",
"node-sass": "^4.12.0",
"sass-loader": "^7.1.0"
},
"babel": {
"presets": [
"react-app"
],
"plugins": [
["transform-decorators-legacy", { "legacy": true, "decoratorsBeforeExport": false }]
]
}
}
But this is throwing me an error as below
I searched online. Everywhere it is showing to add the above options like legacy, decoratorsBeforeExport, but still no luck. I tried removing all the options, keeping one at a time and the above config also for babel plugins. Still, I am getting this issue.