Hi,
The SPA components will render in the SPA Editor, and the AEM WCM Core component will render in the Page Editor, which are 2 different technologies, that share the same UI, but these are not compatible, you can read more here:
https://experienceleague.adobe.com/en/docs/experience-manager-65/content/implementing/developing/spas/spa-overview
https://medium.com/activate-aem/aem-spa-comparison-of-different-approaches-fd5860fb6530
https://experienceleaguecommunities.adobe.com/t5/adobe-experience-manager/using-aem-v-s-aem-spa/m-p/546322
Just to clarify, A "hybrid" approach in the AEM world refers to the SPA Editor, where you can edit content through a WYSIWYG editor, while still leveraging Content Fragments/Sling Model Exporter to expose data and consume it in an "external" application (such as an app written in React).
Hope this helps