Here’s an illustration taken from Cosmology Tutorial - Part 3 that supports the idea of our giant universe. A particularly nice graphic would be this one:
This graphic illustrates 3 different conditions of the early universe where if you added or took away the equivalent of a grain of sand 1 nanosecond after our current time dimension began our universe would be getting crunched or ripped apart right now. So do we need all this stuff? Absolutely!