Tips to improve game performance?

Hello and sorry for reopening an old topic.

I also opened a specific topic:

I read this sentence by Arthuro555:
Separate in separate scenes whatever possible: having a small loading time is better than lagging game

I would like to understand better: does it refer to the number of events or to the number of objects loaded in the editor?

Let me explain: I’m creating a visual novel. The game is very fast and has few on-screen elements (one background, three or four fixed characters, text).

But I have lots of backgrounds (about 100) and characters in the visual editor (about 50).

Is it better to divide them into scenes, or does GDevelop load all the materials only at the start of the game?

If I have 1000 objects in the editor of a single scene but use 5 of them, are there any Ram issues?