I’m using the desktop app v11.84.0 on mac Sequoia 15.5, and I’m no longer seeing an option to export a collection. The context menu when right-clicking on the collection shows very few options (1), and I also don’t see any other settings or options on the Collections tab (2).
(1)
(2)
Welcome to the Postman Community! 
If you create a new Collection, using the + icon on the left next to the filter, are you seeing the Export label in the 3 dot menu?
In the bottom left of the app, can you check if you’re in Local or Cloud View. It looks like you’re in Local view and that Collection is already in the connected local project.
You would be able to find that on your local file system in the connected git project.
You would only have the Export option in the Cloud View.
