Look into:

• API for registering a custom element that will render a Blazor component dynamically
• Making sure nothing weird happens with shadow roots
• Make sure that web component APIs interact well with it (slotted elements - should they map to RenderFragment, or does it somehow magically get rendered as a child because of the web component intrinsics?)
• What do you do when the custom element already has some content? Will you pass it as ChildContent?
• Checking it works well when embedded in a React/Angular/Vue app

Main thing is to check we don't have to ship anything in-box to make this work sensibly.