This preferences option has nothing to do with high-dpi user interface representations. It refers exclusively to image (that is, pixel data) screen renditions.
On macOS with Retina displays, software applications have the option to work either in logical or physical pixels to represent images. A logical pixel comprises four physical pixels on macOS at all Retina resolutions, so the operating system applies an effective 2x magnification factor to the screen coordinate system on all Retina displays. By default, PixInsight represents images using physical pixels on macOS/Retina. This requires generation of 4x the amount of screen data normally rendered at standard resolutions. This preferences option allows you to select logical pixels representations, which are 4x faster but don't make use of native Retina resolutions.
On Linux and Windows, the operating system does not perform automatic screen scaling like macOS. This means that applications always have to work directly with physical pixels on these platforms, and hence the preferences option in question does not make sense.
So yes, PixInsight will *always* use the native screen resolution of your monitor. The screenshot you've posted looks perfectly normal. Why are you saying that PixInsight does not work on your laptop?
If the problem is that you have very little working space, you can fine tune the font dpi setting in Preferences. This works exactly the same way as in version 1.8.4. Bear in mind that irrespective of the native high resolution of your display, the logical display resolution is very low: 1600x900 pixels, probably. The logical resolution is relevant for representation on UI elements (text, buttons, menus, etc.), while the physical resolution is exclusively used to render image data. Without more information, more descriptions or some screenshots, I can't help you better.
