We purchased from "atab" stairs a few years ago (if I remember correctly). It worked well. You can also buy the installation from them.
Keep in mind that with many staircase manufacturers, the railing costs almost as much as the staircase itself. And this often doesn't show in the initial estimate.
There are quite a few staircase manufacturers, and surely more have emerged since we made our choice. If it’s to be a completely straight staircase, a carpenter can probably build it for a reasonable price. A curved staircase is much more efficiently made in a staircase factory. The dimensions of the components are very complicated to calculate for a curved staircase. The factories' CAD programs automate that part.