With the recent changes for scenProc to export to MSFS as well, I have added writing a scenery to a MSFS package to the exporter capabilities. This means that ModelConverterX now also has the same export capability. So if you select “Export scenery” you will be able to export to a MSFS scenery package.
The created package contains a PackageSources folder with the XML and glTF files of your objects and their placement. As well as the PackageDefinitions XML file and a project XML file. This means you can directly compile this package with the MSFS package tool. So this capability can be used to have a quick start with making a package.
If you have just modified a single model, it is probably easier to export it as a glTF file as before and insert the new glTF files in your existing package manually.
For me it is also a bit searching to see which workflow makes most sense for MSFS. So if there are ideas to improve or change the package export, just post your suggestions in the forum.