One of the biggest problems with modern mathematics is the assumption that you can always add one to a number.

In reality this doesn't work.

If you have four apples, then 1 apple + 2 apples = 3 apples.
2 apples + 3 apples is undefined. Or is meaningless.

We may need to choose a largest number, or define a circular set arithmetic.
How many atoms are in the universe is probably a knowable and quantifiable number, and that may be a significant number in place of infinity.