It’s true. If you ask a mathematician what number is the biggest they won’t give you a straight answer.

There is no biggest number. By virtue of the real numbers (the largest orderable set) being unbounded, for every number in R you can find a number larger. You can also find a number smaller for any number.

Indeed, but OP was referencing aleph_0 and aleph_1 etc, the cardinality of the integers and the reals respectively.