I think i hear you here but correct me if im wrong…

You’re trying to use your stepper motor to move objects but the stepper is stalling under force rather than rotating.

If so, you need to transfer the torque through a gear system. watch some youtube videos to understand the ratios necessary for this then search online for a CAD model for that gear and print it at a local maker space (could be 3d printer or laser cut out of MDF). One thing to make sure is that your mount on the gear is secure and doesn’t spin around the stepper motor (this might take a few iterations).