Yes, the top left is showing how many ticks per second being simulated.
I'm not sure why the cells disappear off the left side of the screen. I haven't encounter the issue you mentioned.
I recorded the videos on my computer: https://drive.google.com/drive/folders/1GDncjYbLxKh8OcYmZ7R6h3Cv3pZqUCjc?usp=sha...
The tps will increase if I batch all the jobs together, but it will cause stuttering. As I mentioned in the "possible improvements", using IJob directly for each chunk is likely the solution.