Pie chart is used the best to compare parts of a whole by showing the percentage of each category presented in the chart.
Select the data source that you wish to get insights on, and apply filters as required. At this point, you can filter teams and focus areas only by plans, while you can filter the other entities by Types, Health and so on. While you can choose different combinations of data in the Data Arrangement section, here's a use case to give you more clarity.
If you want to see the percentage of Achieved actions or tasks in your company, you can select Count of Actions as value and then group by Health of actions, you can then see the percentage of Achieved actions vs total of all actions created.
When you're looking at the Count of objectives in a plan, it'll include the shared objectives but not the nested objectives.
You can also filter the actions by a specific or multiple types and choose Count and Percentage to look at the clear visuals.
Use the sort by dropdown to sort the data in the chart - Ascending (lowest to highest values), Descending (Highest to Lowest values), A to Z (sort alphabetically the entity, i.e., objective/measure/team/owner), or click Default to revert to the initial visual.
Hover the mouse over the pie to see the details, and click inside the chart to open the chart context table - you'll see the details like owner, due date, progress, health of the objective/measure/action, and the relevant plan. You can sort the fields, the way you want. If the objectives are chosen, you can further expand or drilldown to view its associated success criteria. Click into any of these rows to open the relevant entity from the Sidebar.