I Have published blazor web assembly project in .net core 6 preview 7
now my dotnet.wasm file size is very large and this has 64mb and its take a few minutes to download and run application In this image you can see the dotnet.wasm file size
i have published AOT Compilation and disabled globalization and other useless peace
You can use the Lazy Load Assembly feature available on .net 6 (and 5).
Look at Microsoft official documentation: https://docs.microsoft.com/en-us/aspnet/core/blazor/webassembly-lazy-load-assemblies?view=aspnetcore-5.0
You can decrease a lot your startup size and load time.
Add <PublishTrimmed>true</PublishTrimmed> to your .csproj (inside PropertyGroup). Trimming will do most of the size reduction for you.
https://docs.microsoft.com/en-us/dotnet/core/deploying/trimming/trimming-options
You can follow the guide at https://docs.microsoft.com/en-us/aspnet/core/blazor/host-and-deploy/webassembly to enable Brotli compression. Afterwards, you can optionally delete the uncompressed as well as the *.gz compressed files. That way, you can reduce the overall size a lot, down to a few megabytes.