Line graph x-axis tick values?

I’ve created a line graph from an excel file with 2 columns for (x,y) pairs. I import the data, but the resulting graph’s x-axis tick values cannot be changed. The x-axis values are the actual x values from the (x,y) pairs instead of just being a normal linearly increasing number line.

I’ve set number format as #.# (only works for y-axis values, not x-axis).
I’ve tried manual settings with {“hAxis”: {“ticks”: [5,10,15,25]}} but nothing happens.
I can’t even set the number of vertical gridlines (there are none, only horizontal).

What am I missing here?