How do you expect the chart to look like with those columns? The full circle would be 286, then checkout and unique purchases are portions of that circle?
We use Quickchart a lot. In my opinion Glide’s chart is limited compared to what Quickchart can provide. A bit of diving in their sandbox environment, a bit of effort to construct the right data to pass in, then copy the sandbox result code back to a construct URL column, then you have a really good chart to display.
Any idea if Quickchart allows funnels? I don’t see that option in their chart gallery. A funnel might be what @Sidney_Kunst is looking for (view → cart → purchase).