I may be rmisemembering this, but as I am replaying the game from a new install, I believe that I was able to scale down the hud(specifically the health portion).
Maybe through an cfg file or something

yes, check hud scaling in cam_ext.cfg (for most people, the auto setting should work best, d3d_disp_scaled_2d_overlay 64).

That command line really only affects the equipment and item elements, but in my memory the health bar was scaled down proportionately to about 1/3 of its original size (1080p)

Honestly it may have just been a dream, oh well. Thank you anyways!

ah yes, those are actually rendered in 3D, so no scaling (as that is for 2D elements only, like text). I think there might be a variable for the 3D elements as well, explore the NewDark documentation.