Hi @emiliano there is not currently a way to embed a video inside the rich text editor. There is a video component that you can add to the page along side any other text / content components.
That being said, if including videos in your rich text is critical, you can always override our rich text editor if there is a library you prefer to use! Simply follow the example of the this plugin: builder/plugin.tsx at main · BuilderIO/builder · GitHub
And register a component within your code base with the name: 'html' and use whatever RTE component you like. That will replace the builder-provided RTE with whatever editor you prefer.
Try it out and let me know if you have any issues or follow up questions!