Noticed a notification for the post I had made awhile back, and thought i’d ensure you’re aware of current requirements.
Blizzard has modified the the Mac version of Warcraft III to be Metal compatible ONLY. This means the solution you may have read regarding OpenGL are no longer valid. Blizzard is focusing on more current gen machines with regards to Macs, hence you will not be able to play WCIII reforged on your current system.
As noted above, unless you have another computer that is compatible with the current requirements, you’re best off getting a refund for reforged while you’re still eligable.
System Requirements:
https://us.forums.blizzard.com/en/warcraft3/t/warcraft-iii-reforged-system-specifications/
You will notice your OS is perfectly compatible, however, your GPU w/ Mac is not and would need to be upgraded to run reforged. Though that may be a little hard considering you’re running a Macbook.
You could try dual booting Windows as your GPU is compatible with dx11, which is required for the windows install. However, I cannot guarantee that i’d work, as your GPU really only supports dx10_1 features, and this can be problematic for games that require dx11. Also, your graphics card is a little underpowered even by minimum required specifications.
Regardless, good luck with however you choose to proceed.