[MacOS] Need help with side mouse buttons not recognised

Hello,

My mouse is a Corsair Harpoon.

This model has two side buttons. I can assign these buttons as bindings on my Windows machine. However when using the same mouse on my Mac laptop, both side button register as "Middle Mouse button"


These buttons perform the task of "forward" and "backward" in a browser and work fine. I have even tested the mouse and can confirm that the correct button input is being recognised outside of PoE.

The M4, M5 and Middle mouse button all register as "Middle mouse button" in game.

Please provide in assistance in reaching a solution.

Update:

I attempted to force the issue by evaluating the keybindings in my windows configuration file and copy them, as they are into the configuration file on the Mac.

The hotkey menu now shows that it recognises Mouse 5 as it's own input. https://i.imgur.com/VKifWmp.png

However, this is not replicated in-game.

The game still treats this as a Middle Mouse Button, despite it showing as Mouse 5. If I bind something else to middle mouse button, that bind will be reproduced when pressing Mouse 5 as will as Middle Mouse button. I am now totally out of ideas.