I have never understood where the confusion comes from. It really isn't hard.
For instance, I have 3 FAA certificates with a total of 6 ratings, 3 endorsements and an authorization.
* Private Pilot Certificate with ASEL, ASES and AMEL ratings.
* Mechanic Certificate with Airframe and Powerplant ratings.
I also hold an Inspection Authorization.
* Remote Pilot Certificate with Small UAS rating.
My endorsements are for my PPC and are tailwheel, high power and complex. When I was a student pilot, I had a few solo endorsements.
A simple way to remember it is if you have a piece of plastic issued by the FAA, you have a Certificate. The type of certificate is written on the front. The ratings are on the back of the certificate. Endorsements are in your logbook.
And, lest I forget I also have a medical certificate so I guess I really have 4 certificates but I don't look at it the same way.
What I do not have are any FAA licenses but I consider the term license to be synonymous with certificate in casual conversations with others, though I would not use the term in any professional correspondence.