In Blazor, the Editable parameter of the column removes it from the built-in popup editor altogether.
If you want to show certain details, you should implement a custom command that shows the desired details in, for example, a TelerikWindow. That's very similar to implementing a custom edit popup (just remove the editors, of course, and put the desired content in the dialog - say, a component that will receive a record ID as a parameter and fetch the necessary data on demand through its OnParametersSetAsync lifecycle method).
Another very similar approach is to use a tooltip to show the row details and load them on demand (it shows the approach I outlined above for using a component and its OnParametersSetAsync method).
You may also find interesting this feature request for a property grid that will display all fields of an object. If so, Vote for it to raise its priority, and Follow it for email status updates.