Is it alright if it's not actually 84,32 or whatever it is, but all objects are scaled up, so it appears as 84,32 (or whatever it is), sorry if I didn't explain it well.
So, from my understanding, it would be ok if the actual game resolution would be 840 x 480, but it still looks as though it was 84 x 48? Or am I misunderstanding?
It is fine to scale. The rule is trying to expressing that you have 84x48 rows and columns of detail. The game resolution does not matter as long as you could make a grid of 84x48 and everything lines up without extra pixels poking out.
I made a reference picture of a 84x48 and 840x480 text. Both are legal the small one is just really hard to read on a 4k monitor.