I love Jira automations. Whenever I start on a new team using Jira, I go in and set up automations that do things like auto-count the subtask story points to fill the parent task's story points, or automatically move tickets to backlog if they don't have fully refined properties (missing user assignment, missing story points, missing priority, missing description, etc). In one sprint the team has a more organized board. Dunno why they're not the defaults, but easy enough to fix with automations.

Why would tickets need to have a user assignment to be considered refined? It should be up to whomever picks it to work to get assigned to, not a part of the refinement.