I think you could see your normals without applying a few months ago (with “adjust edit cage to modifier result” enabled). I used it, but not 100% sure. Probably something broke.
Edit: i think it was working before “triangulate” modifier got “keep normals” option. But i could be wrong.
Well, i said “could” see, i remember it was working some time ago. Now it doesn’t. And suggested that keep normals option was added around that time. It could be related, i don’t know, i’m not a programmer. https://developer.blender.org/rB7d0fcaa69a64eed8a37598213b120582f12fb437
If you know coding maybe you could see if it is related.
Edit : but i think it wasn’t working good anyway. When i was using bevel modifier and weighted normals mod. after it wasn’t working. I think because “adjust edit cage …” option disappear if you do that. So it wasn’t so helpful anyway.