i know its possible with editing the code itself(unless thats misinformation) but idk how to compile
As far as i'm aware, neither legacy or Lua console commands can change the pressure grid size.
PS: Editing the code to change the pressure grid size isn't misinformation, but it's rather laggy
It is impossible without recompiling the game.
If you still want to try, here is the guide for compiling the game, and this is the line you need to change. You will also need to change the line just below to "constexpr Vec2<int> CELLS = Vec2(153 * 4 / CELL, 96 * 4 / CELL);" so the screen size stays the same. Along with what IEATDIRT said about the performance, this will not be compatible with existing saves or official versions of the game, and the air simulation will behave differently. Setting the cell size to one also completely breaks the air simulation and stops gravity from working. If you haven't figured out already, the game wasn't designed with this in mind.
k thanks
ill try some time as i will understand the said stuff i need to do lol