Despite the name, the GPTK isn't just a porting toolkit. It contains a version of Wine that is specifically patched to pass DirectX calls to Metal.

There is a relatively easy way for a player to use GPTK to run games from their Steam library on Mac.

Here is how to use Apple's Game Porting Toolkit to install Wine & Steam.

1. Go to https://github.com/installaware/AGPT and download & run the installer

2. Go to https://store.steampowered.com/about/ and download the installer

3. Open a Terminal, run mkdir Games && gameportingtoolkit ~/Games Downloads/SteamSetup.exe

4. Follow the instructions at https://www.applegamingwiki.com/wiki/Game_Porting_Toolkit#Sh...