There is an opened request for an Accordion style expander (Panelbar) that you can follow here to receive notification emails on status changes. I have added an additional vote on your behalf to increase the feature's priority in our back log.
With that said, I am closing this item as a duplicate of the original Panelbar request to keep the portal clean of duplicates.
In the meantime, I will propose a couple of alternative solutions that you may try to achieve behavior similar to a Panelbar:
Using AnimationContainer component
You could make a component to achieve similar behavior through the AnimationContainer component we provide. Here's a basic example of the functionality so you can tweak it further (and, of course, expose as a stanadalone component in your app, and implement templates and so on)
I have also provided another example with some custom markup that uses existing Telerik classes, and the AnimationContainer - please see the attached file PanelBarSample
Using the TreeView component
Since the TreeView offers expand/collapse animations, you can put generic content in its Template to achieve the similar to Panelbar behavior. You can find more details for the Treeview here.
Virtual Classroom, the free self-paced technical training that gets you up to speed with Telerik and Kendo UI products quickly just got a fresh new look + new and improved content including a brand new Blazor course! Check it out at https://learn.telerik.com/.