I need to do some more work to balance the illumination of the window vs the light coming through, but at least that solves the underlying problem.

TransparentBsdf is good, glass and translucent let color through but too much scatter so it's basically just a big blur, which is probably as it should be. The above is mixing principledbsdf for the glass itself with transparent for the light passing through, and then I boosted the exposure in postFX.