What is the orientation of that window or glass door?
If it were mine I would position the plant right infront of the window, especially if it is a north facing or east facing orientation. You have to open the blinds some more, got to let some light come in. I would also put that container on some sort of platform with wheels, that way you can do some quarter turns a few weeks at a time, to even out light distribution.
If you do not wish to move the plant from that corner, consider either putting a mirror behind it to bounce off some light or use some grow lights.
Also be mindful of watering, Dracaena marginata indoors prefers to be on the drier side.
