This should not be, should it not be, that it finishes the task figure_size and then after the task is finished it should make the png. this seem not procedural or task oriented.
Yes, and it is a decent machine: Intel(R) Core™ i7-7700 CPU @ 3.60GHz with 4 bithread cores. Note that the figures are drawn after the heavy computation is finished.
I am working in Linux Fedora 44 (GNOME Desktop). I have not tested in other environments.