If you're interested to see where we are in building the Fluent UI Blazor library v5...
The demo and docs can be found at https://fluentui-blazor-v5.azurewebsites.net/
Preview (alpha) package is available as well. See https://github.com/microsoft/fluentui-blazor/blob/dev-v5/docs/using-latest-daily.md how you can add the required feed to your environment