Is there any particular reason you're trying to do this?
I have a universal build for phones and tablets. There are 2 cameras: for UI and for World. Scale should be different on tablet and on phone. Most of work is done fine by resolution overrides + zoom on cameras. However
part (not all) of UI sprites need to be scaled differently than other UI on the tablet. I already have these specific sprites in a separate sprite collection.
Solutions I see:
1. Scale single UI sprite collection. I already checked this, by settings scale directly in sprite collection and this works fine. But it works in editor and I need it in runtime.
2. Add 3rd camera for these sprites and zoom the camera.
The 1st solution is preferable, because the project is 90% complete and there is a risk to break something, trying to add new camera and split UI sprites on 2 cameras.
I.e. second solution requires more work (I guess) and contains more risks.