The newly announced Advanced Charts custom widget lets you control the styling much more.
For example, background lines that make it easier to see the position of points in a chart
I’m not sure what you mean here because Grist charts have those background lines and I can see them in your screenshot. But with advanced charts you can configure the spacing and appearance of those lines.
Also the hability to show dates in different formats (I can only get it to show as written month + number year (ex: Jul 23)… but in English language alone!
With advanced charts it’s possible to configure the date format, or to just use the format that’s already in the data without changing it, but I’m afraid it only supports English.
But the chart widget is static i guess. I can´t tell it to be inverted or positive based on the KPI table. I can´t change the TYPE of chart based on the KPI table choices.
Or can I? Through some python trickery?
Not with either of the chart widgets, but if you’re willing to try some more complicated Python trickery, the Jupyter notebook widget can do this.