With a recent rollout(📣 We're bringing swimlanes to business Boards), swimlanes were introduced in Jira Business space boards to help teams better visualise their work, which has shifted the default board structure to use Status as the vertical columns. 

What has changed?

• Vertical Columns: These are now strictly mapped to your workflow Statuses (e.g., To Do, In Progress, Done).

• Horizontal Swimlanes: You can still view your work by Category/ Assignee etc by using the Group by menu, which will display them as horizontal rows (swimlanes) across your status columns.

In the earlier version, the Vertical columns on category basis was a useful setup for many teams to use Board.

Suggest:

Add the ability to display the swimlanes vertically.