As far as I know, you need to make up the ‘missed’ data points, so for your example (0,0), (1,10), (5,10), (7,0), you need to generate a series like this: (0,0), (1,10), (2, 10), (3, 10), (4, 10), (5,10), (6, 10), (7,0) to draw the chart.
Another option is to use Line() widget instead of Chart(). You can first draw an empty chart, so you have the chart background, then draw lines on top of that, but you need to align your lines with the chart background to match the ticks. This is the method I used in my project: https://github.com/dukeduck1984/uReflowOven-Esp32-Micropython . The green line is done with Line(), the red is done with Chart().