This has been a complaint of mine my whole life. As an Anglican, we had greeters, tons of fellowship, coffee hour after the service to greet parishoners and new folks as well as visitors. We got greeted with great gusto and enthusiasm when we came to the Anglican Church and returned briefly to it. As Catholics, quite the opposite.
Catholicism, where fellowship is concerned, still behaves as if it is the Middle Ages and EVERYONE is a Catholic. There was no need for fellowship in the Middle Ages because every single soul in the entire town was a Catholic. You didn’t need to “greet” someone who was already a Catholic becuase all were Catholics (hope that made sense?

)
So to this day the Church has not worked very hard to improve fellowship and welcoming folks into the Church. My parish just sent out a parish survey and one of the questions on there was “do you feel welcomed at each Mass? How is the welcome?” We wrote in “what welcome?” LOL…
At this point I would just focus on the Mass, the liturgy, Christ, and the theology. I would talk to a priest, inquire into RCIA if you’re interested, and check out the lay of the land. With RCIA there is a period of many weeks where one is just welcomed to inquire, no questions asked by the parish and they don’t hound or bother you if you don’t want to join. I would try to get to know folks at RCIA, talk with any Catholics you know at work or friends, keep on hanging around CAF, and try to get to know the Church that way. Mass is purely for worship and there is no fellowship nine times out of ten after Mass unless there is some special feast day, so you’ll come up empty there.
You are correct that fellowship and interaction is one of the weak points of Catholicism. NO argument there.
I’m sorry it wasn’t the experience you hoped for. I’m off to Mass right now.