[wk2jkhkjdfglsl]

one thing, if you were talking keys of length 2048, your talking RSA, and to break it you are applying GNFS, not trying all the numbers up to 2^2048.

2^2048 is so astronomically large a number it has no universe sized meaning, its likely way way more than any discrete chunking you can do of stuff in the whole universe.

Something like 2^128 or 2^256 are more common 'brute' force type numbers, which would correspond to trying every key in a symmetric cipher like AES or a public key signature in ECDSA

2^256 is similarly quite large, but we can practically estimate this to be about the number of atoms in tens of thousands of galaxies.