The new Carousel component is not found in the Toolbox panel. Did you forget to add it?
use the EXE file at the address of https://cdn.radzen.com/Radzen%20Blazor%20Studio%20Setup%201.34.0.exe to update, not see the content of the new version of the update.
You also have to make sure you are using the 5.3.0 of the Radzen.Blazor package. RadzenCarousel is not available in earlier versions hence it won't appear in the toolbox.