I have the habit of taking things apart to check if there is something useful for modelling inside.
Cables contain copper wires of various thicknesses.
When I disassembled the cable on some broken mobile phone earplugs I found that the shielding consisted of a narrow strip of thin copper foil wound around the wires inside. They were less than 1 mm wide and my thought then was that they would be ideal for safety harness belts.
Another possibility is to use thin copper wire (or aluminum if you can get hold of thin alu-wire). Fasten (tape down the ends) short pieces on a hard (steel plate) surface and flatten them by rolling a steel pipe (or other hard cylinder) along them (press hard).
Copper can be softened, if needed, by heating with a flame.
The rolling will flatten the wire and also make it slightly longer so you may need to adjust the adhesive tapes holding them down. The flattened wire will have rounded edges and be smooth so they willresemble leather straps.