Hi @bangar20 ,
Unfortunately, React SPAs in AEM don't directly support inserting Parsys or using Sightly within your React component. React handles client-side rendering, while Sightly is server-side.
If you need React and Sightly components on the same page, then probably you can try below approache
Create two separate containers on your page, One container for React components (e.g., <div id="spa-root"></div>). AEM provides a "Layout Container" component specifically designed for React SPA development. This component allows you to define a layout structure within your React component and specify areas where child components can be dropped.
Another container for HTL components (e.g., <div id="responsive-root"></div>).
Inject HTL components into the second container once the React page is loaded.