Hi @Naama, could you tell what is not working properly for you using the built in video component? To style embedded video as responsive, check this article: [Tutorial] Responsive Video using HTML Embed - Webflow Tips - Forum | Webflow
Regarding the autoplay on mobile, that is disabled in iOS by default, and normally shows the play button (assuming the embed code options are correct).
My advice would be to use the built in lightbox for your youtube videos, or create a custom modal and then control the video playback/controls using javascript instead of an using an iframe.