.NET 6 Preview 1 bits were released yesterday (info below)...
.NET 6 Preview 1 for Blazor WebAssembly (WASM) includes many performance enhancements planned. For example, in Preview 1 the interpreter has been improved greatly. This gives Blazor WASM a VERY nice performance bump in .NET 6 for "FREE" by just using the new .NET 6 runtime.
Run the performance tests yourselves and compare!
.NET 6 - https://statisticsandblazordotnet6.azureedge.net/
.NET 5 - https://statisticsandblazordotnet5.azureedge.net/
.NET 3 (Core) - https://statisticsandblazordotnetcore3.azureedge.net/