Edit STEP (stp) file of a Device in AutoCAD -- 2

I need a dependable 3D pro to open my existing .stp file, sign a simple NDA, and apply focused updates. I already have the exact measurements—your task is to:

• Tweak the device’s shape where marked
• Add or remove the specified components
• Rescale parts to match my provided dimensions

All work must be carried out in AutoCAD or any app that can be save as or exported as stp output. Once done, send back the updated STEP file along with the editable source so I can verify every change. Accuracy and clean layer naming are essential.

If you’ve done similar quick-turn hardware edits, feel free to share one as a reference. Please confirm your turnaround time and any questions you have before we start.