After deleting a bookmark (control-delete) confirmation options in the pop-up are only selectable by mouse/trackpad. Cancel is the default, continue is not keyboard selectable.
OS 13.4 Hookmark Version 5.1.3 (5475; Integration v. 278)
edit: I quit Stage Manager and Better Snap and restarted. No change.
Nope! I also tried clicking on the popup just to insure it had focus.
Got it! My bad, keyboard nav was not selected in apple settings.
Great! I am glad you solved the issue.