I can also confirm that the freezes are gone after removing the “Global AI Ship Traffic” mod. Apparently, the ship model conversion (that is done when the sim loads a ship in an older format) causes the issues. An update that no longer needs conversions during loading is worked on, but may take some time:
If you want to completely remove the mod in the meantime, you should also remove the auto-generated gaist CVT folder in your community folder and the folder %appdata%\Microsoft Flight Simulator\$PC$ which can be several GB in size.