There are some limitations to this library.
We cannot render React Native views directly to the widget. What this library does is render the React Native views to an image, and then show that image in the widget. For it to look good, we need to know the exact size of the widget, so we can create an image that will fit the widget correctly.
On some Android launchers, the reported and actual size of the widget are not always the same.
I haven't found a reliable way to get the exact size, the current behavior is to crop the widget if the reported size is smaller.