How to calculate approximate RSA decryption time?

Question

RSA

The user has exactly 30 minutes to use the cipher, after which the cipher becomes irrelevant. It is necessary to choose the minimum sufficient bit depth of the RSA algorithm, which will provide resistance to hacking. Please understand correctly, if you do not recognize RSA up to 2048 bits, do not answer in this thread.

Answer 1

Do you understand that key selection is pure randomness? You may need to go through absolutely all the options, or maybe you get lucky at the first iteration. So only the upper bound can be calculated.