At first, .NET 6 and .NET 7 versions of .NET MAUI were released only via SDK Workloads whereas from .NET 8 onwards (Preview 4 to be precise), it is now distributed as a base workload and suite of NuGet packages on top of it.
This NuGet-based release process allows trying different versions of .NET MAUI which are released on top of a base workload on the same machine without the complexities of moving between different workload versions.