Why does all cold/offline storage setup require three steps?
Building the unsigned transaction requires the input data(transaction IDs, vout, values), and is also good practice to check the network fee climate prior to setting a fee in the transaction you are building.
Technically yes you could do it in two steps but it would be considered for advanced users only and still prone to typos or other errors during the input data entry.
Related repository of mine that lets you skip step 1 and do it in 2 steps if you choose. (NOT A RECOMMENDATION, EXAMPLE ONLY TEST SOFTWARE USE AT OWN RISK) https://coinables.github.io/coldsigner/