Complex collision mesh

i have a problem with using a mesh as another’s complex collision
it’s a stair asset i have exported from megascans using auto convex wasn’t so well and the complex collision has way too any verts so i decided importing the mesh into blender and making a simpler mesh to be used as the collision
i have tried creating a completely new mesh with collision setup as UCX_ but once imported it simplifies it
i’m not even sure if it’s the right way but i don’t no of any others
please help

here’s a video of my problem :

Even if you use UCX objects it will force it into a convex shape. Either make a ramp like collider or use lots of UBX colliders ( 1 per step )

thanks a lot it really helped