Uploading photos from MacOS Photos to Facebook? What is the "simplest" and most privacy-conscious way to upload photos from your MacOS Photos collection to Facebook?

I "trust" Facebook as little as possible (for obvious reasons) and so do not want to do anything that would give it full unrestricted access to my Photos collection.

MacOS has a Facebook "Extension" which allows Facebook to be added as a destination to the Photos "Share" menu, but I am very wary of enabling this and do not know what permissions it would give to Facebook. (I recall reading somewhere that, on iOS, if the Facebook app is given access to the iOS Photos collection, the Facebook app then automatically "helpfully" uploads all of your photos to Facebook, which is the sort of thing that I definitely do not want.)

At present, to upload a photo to Facebook, I seem to have to export the photo from Photos, go to Facebook in my web browser, and then select "Upload photo", and then navigate to the folder where I exported the photo in order to upload it. This is a somewhat cumbersome process. It would be useful if I could instead more simply "copy" a single photo from Photos and then "paste" it into my Facebook photo collection somehow, but unless I am missing something, this does not seem to be possible?

Is it a case of: ease of use, security; pick only one?
You kind of answered your questions yourself. 

Never trust a proprietary extension or app, because you never know what the app is doing. Today it's normal for an app to collect all personal data technically possible. Facebook is evil. Exception is an Open Source client, where you can see the code.

To grant Facebook as little as possible data, you need to use their web interface (not app) and install essential privacy extensions and Ad blocker. See PrivacyTools for a list of recommendations.