Is it possible to embed a Blazor component in a non .NET website?

Yes. This is possible. Once you publish client-side Blazor application using dotnet publish resulting files can be served from any static file hosting. For example you could serve the results using http-server . from the folder where results are published.

To control appearance where Blazor application would be visible in the final HTML application, you can augment index.html as you see fit. <app> tag would be replaced by Blazor application.

Should be possible. From here: https://learn.microsoft.com/en-us/aspnet/core/blazor/hosting-models?view=aspnetcore-3.0:

An ASP.NET Core web server isn't required to host the app. Serverless deployment scenarios are possible (for example, serving the app from a CDN).

If I publish a client-side Blazor project within Visual Studio to the file system then I get the index.html, css folder and a _framework folder containing the js and wasm files.

I guess it should be possible to serve those from wherever, but not tried it.