FileSystemWatcher-Event and Calls to Com-Objects in .net Core

I have code like this in an .net core C#-Library. It tries to monitor a directory and process files either becuase the user Refreshes or the file changes

public class WatchedFolder
    private FileSystemWatcher _fileWatcher;
        
    public WatchedFolder(){
        _fileWatcher = new FileSystemWatcher(@"C:\Myfolder", "*.txt")
        {
            NotifyFilter = NotifyFilters.LastWrite,
        };
        _fileWatcher.Changed += OnFilewatcherChangedFile;
    }
        
    private void OnFilewatcherChangedFile(object sender, FileSystemEventArgs e){
        processFile(e.FullPath);
    }
        
    //May be called in reaction to FileSystemWatcher-Event or directly via User-Button-Click in the GUI
    public void processFile(string sFilename){
        //Create native Com-Component to process the file
        PPBinExportLib.IAVBinExport ppBinExport = new PPBinExportLib.AVBinExport();
        ppBinExport.process(sFilename);
        Marshal.FinalReleaseComObject(ppBinExport);
    }
}

When I call processFile directly from the GUI everything works fine but if called from OnFilewatcherChangedFile I get an excepton when trying to create the com-component.

The native errorcode I get is 0x80010106 which means "Der Threadmodus kann nicht nach dem Einstellen geändert werden." (just have a german windows but it means something like you cannot change threadingmode). However, I see that the Com-Component may call CoInitialize to single-threaded. It may be wrong to do so anyway but I cannot change it easily.

Since I know in .net core the FileSystemWatcher runs in another thread, I have a feeling this might be the problem? Using the Com-Component from the main-Thread works, from the FileSystemWatcher-Thread doesn't.

So how to fix this? I think I have to use FileSystemWatcher.SynchronizingObject and the ISynchronizeInvoke-Interface but how to do this?

Regards Micha