Thanks for the reply Matt 
Here is what my v144 directory looks like, with the full path visible as well:
https://i.gyazo.com/25bf16df262bf8a70900bd32e8e52160.png
Then, this is what my Steamworks.build.cs looks like:
https://i.gyazo.com/03eee6bbe6925ecfdb478ea8e18df553.png
From what I can see, it should be looking for the directory Steamworks/Steamv144/sdk which definitely exists as shown above. However, I’m still unable to compile and I’m completely stumped 