Lunashops also has an AliExpress store, I would order from there instead. Cables for the ER4B/S/P must have a resistor in it (22 for P, 100 for S), a lot of Lunashops' cables do not have a resistor in them.
They have one, LN005997, you could try out that one, but I've had the ER2/ER3/new ER4 equivalent, LN006057 and the build quality was not very good. They also have the LN007628 which has an adjustable resistor in it. I have their other adjustable resistor cable, LN007689, which I bought for the ER3SE, and the build quality is very good.
IIRC the best recable "mod" for the ER4B/S/P is buying an adapter that lets you use any regular MMCX cable with the ety. This adapter must have a resistor in it so you still get the original sound.