to use Aztec SDK and create-react-app 5 with https://www.npmjs.com/package/react-app-rewired

config-overrides.js

const webpack = require('webpack');
const CopyPlugin = require('copy-webpack-plugin');

module.exports = function override(config) {
  let fallback = config.resolve.fallback || {};

  // These fallbacks are required for the @aztec/sdk v2.1.0-testnet.30 or greater
  Object.assign(fallback, {
    "crypto": require.resolve("crypto-browserify"),
    "stream": require.resolve("stream-browserify"),
    "path": require.resolve("path-browserify"),
    "assert": require.resolve("assert"),
    "http": require.resolve("stream-http"),
    "https": require.resolve("https-browserify"),
    "os": require.resolve("os-browserify"),
    "url": require.resolve("url"),
    "fs": require.resolve("browserify-fs")
  })

  let plugins = [
    // Only required for @aztec/sdk v2.1.0-testnet.30 or greater, not for v2.0.112
    new webpack.ProvidePlugin({
      process: 'process/browser.js',
      Buffer: ['buffer', 'Buffer'],
    }),

    // These file locations are specific to @aztec/sdk v2.1.0-testnet.30
    new CopyPlugin({
      patterns: [
        {
          from: './node_modules/@aztec/barretenberg/wasm/barretenberg.wasm',
          to: '[name][ext]',
        },
        {
          from: './node_modules/@aztec/barretenberg/worker.js',
          to: '[name][ext]',
        }
      ],
    })
  ]

  config.resolve.fallback = fallback;
  config.plugins = (config.plugins || []).concat(plugins);
  config.ignoreWarnings = [/Failed to parse source map/];

  return config;
}