Hi Jonas, the makeStyles is not a function error usually comes from version mismatches between React and Material UI. Since the React template loads dependencies via <script> tags, it’s possible that the latest version you’re loading includes breaking changes.
We recommend locking both React and Material UI to specific versions known to work together—like React 17 with Material UI 4.12.4. You can find an example setup here that uses fixed versions: A-Frame: React Material UI | 8th Wall | 8th Wall