If you plan to share then mdl files are depreciated and should be replaced with gltf.
If you have ADE and preferably FSX but possibly a P3D then you can generate basic XML for the airport and use that as the basis of the source xml in a FS2020 package. The FS2020 schema seems to accept most FSX and P3D XML but reports some errors. We are working on a version of ADE for FS2020.
Removal of autogen and scenery objects can be achieved in the FS2020 Editor
If you need more information please ask
If you have ADE and preferably FSX but possibly a P3D then you can generate basic XML for the airport and use that as the basis of the source xml in a FS2020 package. The FS2020 schema seems to accept most FSX and P3D XML but reports some errors. We are working on a version of ADE for FS2020.
Removal of autogen and scenery objects can be achieved in the FS2020 Editor
If you need more information please ask