Model is Senheiser Momentum2 HD1 Bluetooth (over ear) PF edition.
I have wrapped electrical tape over it but cables on both sides have started to disintegrate/decompose.
I know next to nothing about audio cables. I care more about functional quality then original looks so i would be willing to swap the entire cable for a more permanent one, but i wouldn't want them to look ugly either and need to find a good way to fit them to the earshell.
Just get some thin 2 wire cable, and replace, you can essentially use whatever cable you want. It may not be shielded, but it will work just the same. Even inside of Ethernet cable is good usable wires.