But you are marked forever as a Catholic. The fault wasn’t in the Baptism, but in the lack of catechesis you (didn’t) receive.
You are welcome to come back to the Catholic Church at any time. All you need to do is sit down with a priest and get your questions answered. Which would lead to other steps, of course.
I really have no desire to come back to the Catholic church. I am well versed in the Gospel and know that I am saved by Grace.