Much more better, moving the directory to the root reduced the nummber of errors to 3.
Severity Code Description Project File Line Suppression State
Error C3861 ‘GetEditorForGraph’: identifier not found UE5 C:\UnrealEngine\Engine\Plugins\Runtime\Metasound\Source\MetasoundEditor\Private\MetasoundNodeDetailCustomization.h 318
Error C2036 ‘const FWorldPartitionStreamingQuerySource *’: unknown size UE5 C:\UnrealEngine\Engine\Source\Runtime\Core\Public\Containers\Array.h 2712
Error C2027 use of undefined type ‘Metasound::Editor::FGraphBuilder’ UE5 C:\UnrealEngine\Engine\Plugins\Runtime\Metasound\Source\MetasoundEditor\Private\MetasoundNodeDetailCustomization.h 318