With next-gen jira, I don't understand the design choice to display the board view grouped with subtasks the way Atlassian has chosen to do it. The display is that each task is displayed with its subtasks below it in their lane; then the next and so on. Tasks without subtasks are displayed below all those that have subtasks on the board.
It seems to me that displaying subtasks on the board via a checkbox as in classic and having them appear alongside every other card to then be moved around made a lot of sense.
This new display mode calls for an almost impossible amount of verticle scrolling leading to it being impossible to get a complete and clear view of the entire board.