2019.3 / 21.3.0.3250
Hardware: HP Spectre x360 (i7-8750H, 16GB, GTX 1050Ti MaxQ)
*UPDATE*
It seems like the issue is isolated when moving the application to an external 4K display connected via a Thunderbolt 3 Dock. (HP Thunderbolt Dock G2)
When booting the application memory usage is @ 1-2 GB. (4 way split, Viewport Standard mode)
Going Fullscreen it ramps up to 4GB. This is with nothing in the scene. Fullscreen High Quality is 8.2GB.
Actually loading a simple low poly character sees it jump up to 10.5GB with GPU usage @ 100%.