I created a MAUI-Blazor project with VS 2022.
and installed Microsoft.Fast.Components.FluentUI 2.3.2

Add @using Microsoft.Fast.Components.FluentUI in _Imports.razor.

Add tag in index.html

Followed documents modified Promgram.cs

Add sample code in index.razor

<FluentCard Style="padding: 1.5rem; width: 400px; height: 250px; ">
  <h2>Hello World!</h2>
  <FluentButton Appearance="@Appearance.Accent">Click Me</FluentButton>
</FluentCard>

App can not work well.

If add web-component script in index.html.

it will work well.