Pixel-art: how to cook for different diagonals and resolutions?

Question

Game development

Hello!
Noob question. More or less I have an idea about the resolution: if you draw a picture at one resolution, and display it at a larger one, then the picture will become smaller, decrease. There is an idea to draw a noir pixel art game.
1. There are lines of tablets, smartphones of different brands and desktops. Is there any reference resolution-density for the artist?
2. Is scaling so that the image looks pixel-by-pixel the same on different screens, can be done using game engines, or is this not always possible?

Answer 1

Error in terminology in both paragraphs.
When displayed in a higher resolution, the picture does not become smaller, it is the same pixel by pixel, but the pixels themselves are smaller and the picture looks smaller.
When scaling (by any algorithm), the picture will not look the same pixel by pixel, because it is scaled and the number of these same pixels has become different.
You can make graphics for the extension 1280*720 (for example), and scale for all other resolutions. When reduced, it will look a little worse (not very scary). With an increase, it will blur a little, which again is not very scary (the pixels are already small and artifacts will be very noticeable only if you specifically look for them).
You can make sprite sets for two or three of the most common resolutions. But in my opinion, the HD version with scaling is enough for everyone else.

Answer 2

So, do not bother with scaling issues - leave it to the engine, just look visually: if it "looms" - redraw it with a higher resolution?
I found a site with a list of screen resolutions for smartphones and tablets . The darkness of all kinds of resolutions - if you determine by trial method at what resolution the chart starts to "soap", you will probably need the entire line of devices for tests. Maybe there is some kind of "golden mean" in resolution? So that you can scale both on retina and on smaller resolutions? For example, iPhones and iPads. If we take Iphone 4\5 and iPad with retina as the target device, then what resolution should I take?