What soundtrack is your reference? in a traditional orchestral style, the feeling of width often comes from recording and orchestration more than mixing techniques.
For example, spaced mic pairs like "outriggers" or Decca tree will be good for a 3d spatial image compared to coincident mic techniques. And capturing a bit of the room in those mic positions also add more feeling of width in the recording. So if you can use Decca mic positions or similar in your template over close mics, that could be worth a try.
But even more important could be orchestration. Layering too much can actually smooth out the high frequencies that would have given clarity and power to each instrument, and the result becomes more muddy and vaguely centered. Instead, assigning separate notes of a chord to individual wind instruments, or individual string sections, will spread the music in stereo, and it will also allow the brightness/clarity of each instrument to shine on its own even when the entire orchestra is playing.
Great examples of these points are the Andy Blaney demos for spitfire symphonic brass. I've heard those were done using outriggers only, but I don't really know.
Do you feel like these points might explain some width that you're hearing in your reference track, or do you feel it's something else?
In this track it feels like there is a fair bit of distance between the dueling string lines. Also when the horns come in they feel reasonably to the left.