better support for very large worlds

I am trying to render a simple 2D map for a 10k-radius world.

After waiting for a long time for the world to load and to hand-select all chunks, chunky freezes up when creating a new scene.
Would it be possible to not have the preview window open by default (or a way to deselect in in options) ? One is not able to save the scene file due to chunky freezing up in the scene gui.

Also, would it be possible to have a "full world" support for a 2D map headless render ? Having to use a gui to create a scene file before using the headless mode is difficult when using a terminal-only server (copying full world and scene file back&forth).
Maybe adding the option --full2Drender for the headless mode, would bypass the scene chunk info and start rendering the entire world.

If there maybe is an easier way to do it, please let me know.

(Tried rendering 2D world map consisting of 380k chunks. PC freezes up at loading 230k chunks, using AMD FX-6100 6core, 32G RAM, 110G swapfile )