The new funnel chart in Looker Studio doesn’t work the same way as Community ones. In Funnel Metrics for example we can use only metrics without dimensions and it is working perfectly. How can the new native Looker Studio funnel chart works
Indeed, you need to adapt your data model to fit how the configuration of the native chart type.
So, in your example, the dimension needs to be “Item action” valued with “Viewed”, “Clicked in list”…and the metric “Item count”. Both must be calculated thanks to a blending if you are loading yourGA4 data directly with the native connector.
So, if the current custom viz fits your needs, I would recommend to keep it for the moment.
Sherry has used a custom visualization allowing to configure a list of metrics for the funnel. The native and freshly released funnel chart requires a different data model. Since the creation of this ticket, I wrote an article describing how to adapt the data model to fit with the native funnel chart: