[General Topics] 90dfx:
Ok, here goes the trick about making your primary screen larger and its disadvantages, hopefully someone can figure out a better way to may it work.

The way flexpai 2 primary screen size works is, the system multiplies the whole landscape resolution by certain ratio and that's what use get as for the screen width. It is probably using about 40% of screen real state in landscape mode and this is a ratio that I haven't figured out how to change, however what we can change is the resolution. By increasing the whole screen resolution we increase the primary screen size, while keeping that default 40% percent usage.

Disadvantages of doing this are:

that mostly top side and right side of the screen becomes unusable. They stop detecting input, so the bigger the resolution the bigger are of usage you loose, this affects even nagivation gestures and any buttons in apps. One way to reduce this disadvantage is by increasing your DPI so screeen elements become larger so you can still click them if they are on top side or right side.

UI is not made for this resolution change, so home screen app and some other system screens, may not behave properly. This apply aswell to recent apps (multitasking view). One way to reduce this other disadvantage is by installing a third party home screen, activating gestures, enabling a third party gestures app like "edge gestures" and since default launcher doesn't let you keep using multitasking view once you move to a third party launcher, you will need a third party app to switch between apps like "recent app" (search it in aurora store or others), and set it on your third party gestures app to be launched given certain conditions. You will also need to use gestures that doesn't go against current default gestures. You can also use third party gestures app if your status screen is not anymore reachable, just set up a gesture to call it.

Unfolded mode on portrait and reverse landscape becomes more difficult to use because your bottom side will never be usable, and you wont be able to call gestures from there. One way to fight this is by always using it in reverse portrait mode if you have it unfolded and regular landscape mode aswell. You can download an app called "orientation control". This is the only one I have found that allows you to use reverse portrait mode while having enabled forced rotation, so reverse portrait mode can be automatically activated once you rotate device.

In order to make it work, you will need:

keyboard that also allows you to be resized, since you will loose touchscreen area in folded and unfolded state. I use an old Microsoft swiftkey version that came in 2020, that allows you to resize it towards one size of the screen in unfolded state.

Third party app resolution changer, like "second screen"

Change resolution to 2000*1500, for example. You can use a DPI of 500 to make buttons larger and reachable and use a third party app to make fonts smaller. The bigger the resolution, the larger the touchscreen area you will loose. A resolution of 1960*1470 will pretty much allow you to use almost any gesture while gaining screen real state. As a suggestion, let "safe mode" enabled on settings app just in case something goes wrong.

Hope anyone finds this information useful. I just can't go back now to the default screen size because I love how my Flexpai 2 looks with the larger primary screen size. I'm guessing this should work with original Flexpai aswell.