Just an off the wall idea but could you install a one way uv reflective film on the underside of the playfield glass and high intensity uv LEDs on the front of the apron? Would the film give you enough bounce to light the playfield? I have no idea if that would work.
https://tinyurl.com/vox29sg
https://tinyurl.com/wcubyf9
https://tinyurl.com/u94xtrb