Launching new apps splits screen space by half automatically. How to disable this?

Whenever I open/launch new apps , the existing app moves to one side of screen , kind of like splits the screen space by half automatically (in the same monitor and same workspace) . I want the newly opened app to be in the foreground, instead of be in a split screen.

I don't know if this a feature i enabled unknowingly. I have gnome tweaks installed , but i don't see any split screen option in gnome tweaks settings .Any help would be appreciated .

The behavior you describe is the normal behavior of a tiling window manager. Gnome Shell is not a tiling Window manager. If your system behaves like one anyhow, then you must have some extension installed that causes this behaviour.

Thus, inspect all the Gnome Shell extensions you have installed, and disable them one by one to discover which one causes this behavior. You can see your extensions in Gnome Tweaks.