Floating stairs are often a beautiful feat of architecture. The support systems are hidden and it becomes a stunning piece of art for your back yard. However, building floating stairs can be an architectural nightmare.
Large metal beams are cumbersome to lift and attach. Welding is time consuming and will never finish on the first day. Not to mention that the measurements must be extra precise for every single attachment point, and all of these matters are happening before considering building code.
Unless you’re an architect, engineer, and metal fabricator, the chances of building a floating staircase on your own is slim. There are substitute options, of course, that could bandaid your problems, but those are not guaranteed to meet code and may actually be pretty ugly. This is when it's time to call the pros.