Can't seem to write to the status register of nRFL2401+
You misunderstood how it works. You can't write it to 0x7E yourself. The bits get set to '1' by the chip only when a corresponding IRQ event happens.
When the chip has set any of these bits high, they are cleared by the user, by writing a '1' bit to the location you want to clear/acknowledge back to '0'.
So when the register is 0x0E, no interrupts are pending, and there is nothing to clear.