As of ArcGIS Insights 2021.3.1 for ArcGIS Enterprise, Predefined filters widget/card supports single select dropdown, single-select list and multi-select list options. In case of multi-select option, the card occupies too much space and it's impossible to resize it to a smaller size.
It'd be great to have a multi-select dropdown option as well, so that filters don't take up too much UI space.