Block universe+eternal universe= infinite universe?
I'm not sure you are right. There are different types of infinities so an object might be infinite in some ways but not in others. I hear many physicists say that the universe can be infinite and bounded at the same time. There is Gabriel's Horn as well (something finite with an infinite surface area)
My personal opinion is that "A Time" is correct and that the past is not infinite because time is always slipping away. Talking about objective experience is hard because of all the ways we take up reality, construe, and interpret it. In a sense we feel, when we are honest with ourselves, that we construct the world. Experience is not "meant" on it own because it's hard to conceive what is purely given to us. We make our own self consciousness and choose ways of saying the world.
However, if time is objectively an eternal instant and infinite motions hold together frozen in that instant, it seems to me the series would be geometrically infinite. How to understand the infinite is hard nonetheless