for embeding i use community plugin called Simple Embeds, but it works only in ‘Read mode’, while iframe works in ‘Edit mode’.
obsidian://show-plugin?id=simple-embeds
If you don’t usually edit those notes with youtubes you could use ‘Force note view mode by front matter’ plugin to save couple of clicks, by setting default ‘Preview mode’ in YAML section of those video notes. Plugin link:
obsidian://show-plugin?id=obsidian-view-mode-by-frontmatter