Tried using a spiral wrapped around the cone as a curve to make the stairs array follow, but the stairs array either disappears when I try to link it to that spiral curve or it gets crazy :) any help please?
You could use a lattice object to bend your staircase.
I used a single vertex and a screw modifier to get a spiral :
Then another screw modifier to create small faces oriented along the tangent of the staircase. This will help orient the steps afterwards.
Create your step object and parent it to staircase using CTRL + P
Go into the spiral object properties and enable instancing on faces.
Should look like that :
Create a lattice object, scale it in OBJECT mode so it's slightly bigger than your staircase.
Add a Lattice modifier to the staircase object
Select the lattice, go into EDIT mode and scale the top 4 vertices down.
Afterwards you can disable the spiral rendering in viewport and render :
If you want more usability you can add a shape key to the lattice before editing it in edit mode. Add another one directly after and modify the lattice the lattice in edit mode while the second shape key is selected. You can go overboard since we'll be using the slider to adjust the effect.
You'll notice the steps are instanced at an angle, that's because the vertical faces get rotated by the lattice. Simple solution is to place the lattice modifier in second position in the modifier stack :
You can even add another shape key to tweak the spiral height.
Play with the first Screw modifier to change the staircase :
Inspired by Moonboots :)
This answer is inspired by Gorgious' answer here.
First array a simple edge along your spiral, put the edge object origin at the exact same position as the spiral origin, use the Array "Constant Offset" option, otherwise you won't be able to array it. Then give your edge a Screw modifier with an Angle of 0° and a Steps of 1 in order to create planes from each edge. Your curve must have its Shape > Twist Method set to Up.
Create your stair step, parent it to the edge. Select the edge, go in the Properties panel > Object > Instancing, enable Faces. The step should be duplicated on each edge position: