Cannot connect Sony WH-CH500 headphones to iMac.

I'm currently running an iMac Mid 2011 with macOS High Sierra v10.13.4 installed. The bluetooth's module which is active at the moment has v6.0.5f3 (v208 c518).

I tried reseting (including alt+shift -> Debug) the Bluetooth with no luck at all; the headphones simply won't appear in the dropdown list. The Bluetooth Preference's window merely shows my Keyboard and Mouse that are connected. It might be worth mentioning that the Headphones do work with my smartphone, running iOS.

The official website Sony UK does not include any drivers, which probably means that these headphones where made/meant to connect solely with bluetooth devices like smartphones, but not with computers? This does not make sense at all.

Are there any drivers, perhaps open-source (Linux included), which I can install to either update/debug the current module?

Are there drivers for implementing a smartphone bluetooth module, like the one running on my iOS, to make my present module on the iMac act like "sorts of a smartphone". Hence, this may trick the headphones into connecting to a smartphone device but actually pairing them with my computer.

Any quick feedback is well appreciated, else I will just opt for the more sensible option by returning these headphones and buying a compatible pair instead.