yarn add -D @babel/preset-{env,react,proposal-class-properties}

.babelrc

{
  "plugins": [
    [
       "@babel/plugin-proposal-class-properties", {"loose": true}
    ]
  ],
  "presets": [
    [
      "@babel/preset-env", {
        "modules": "commonjs",
        "targets": {
          "node": "current"
        }
      },
    ],
    "@babel/preset-react"
  ],
}

If I got that correct this time around, that first plugin (class-properties) is the solution, or one. It may be mentioned already in one of your links. I don’t have a big issue with: class-autobind in the constructor really either.