Stair length: What is the optimal length of a staircase?

My problem is that I don’t quite understand. What do the numbers mean?

You said 330 cm stair length. With 14 risers I get (330 cm : 13 treads) 25.4 cm tread length, which, with the recommended measure of 63 cm made up of 2x tread length plus 1x riser height, results in 18.8 cm riser height. And 14x 18.8 cm riser height in turn equals 263.2 cm. You said 250 cm room height, so the ceiling would have to be 13.2 cm thin (and that also with flooring on top), which is absolutely impossible. For a more realistic 280 cm story height, one would have 17.5 cm riser height with more comfortable 16 risers (and then 28 cm tread length x15 = 420 cm).

250 cm plus 20 cm ceiling plus 18 cm structure = 288 cm. Divided by 16 results in 18.0 cm rise. Corresponding to that is a 27.0 cm going. Stair length 16 x 27 = 432 cm, with the top step heightwise transitioning into the surface above. Depending on how one wants to do it. Without the top step (16 - 1) x 27 = 405 cm.