- Click on A icon on the top left corner of the screen and go to Options
- Go to Profiles and select AutoCAD. Click on Set Current and OK.
- Now the 3D workspace should be enabled under 'workspace switching' icon
Thanks to CTT for the tip :)
Now why wasn't this enabled in the first place??
Because the objects in AutoCAD Architecture software describe real-world building components, both 2D and 3D representations can be created automatically and either can be used for viewing or editing. This capability conveniently integrates 2D and 3D functionality and enables exploration of design ideas within CAD in a fashion similar to the way architects and designers envision their designs.
Using 3D is not required in AutoCAD Architecture software; you can incorporate 3D into your design process at your own pace.
More can be read here: