The problem with the majority science view is that their/your model has space which consists of bounded abstract metrics allegedly expanding, yet having no outside of to expand into, this having allegedly been going on for 15 billion or so years from the alleged singularity submicroscopic particle of space.
If you have the set of all even numbers, that's an infinite set. It's infinitely large. If you put each number in the set on a yardstick, one inch apart, that yardstick would be infinite in both directions (positive and negative).
Now, lets say that you decided to expand that set by adding the odd numbers, one by one. You keep the sequence of the numbers in order and you maintain the one-inch spacing. That means as you put in an odd number you have to push all the subsequent numbers down an inch.
That means your yardstick is expanding, because you're inserting new length between each even number. The distance between any two numbers increases relative to the original distance between them - for instance, the distance between 1 and 100 grows more than the distance between 1 and 20 by the time you're done.
So what do you have? A growing yardstick of infinite length. It doesn't need non-yardstick length to
grow into, because its length isn't changing. (The set of all integers is known to be the same size of the set of even or odd numbers.) But it is, nonetheless, growing at each point.
Just because something is infinite doesn't mean it can't grow. It grows without changing size. Your mistake is applying the common sense you developed on finite entities to infinite entities. It just works differently. (And it actually makes sense once you learn the rules.)