Joshua Hoblitt, sorry not enough info in this ticket.
Fix was to return run summary in latestRun instead of full Run object graph. See https://github.com/jenkinsci/blueocean-plugin/pull/1635.
Dashbaord lists pipelines and favorites. In both cases each pipeline also includes 'latestRun' property that includes complete Run object. Run objects can be very expensive and includes expensive objects such as changeSets and many others. Further, it was validated to be the case going over HAR files submitted by users on this ticket and others.
Favorites can be expensive too, specially it was resulting in to expensive computation and fact that we autofavorite and need all favorites so that we can show in pipeline/branch/activities pages - had more involved fixes. This is fixed as well, see PR https://github.com/jenkinsci/blueocean-plugin/pull/1638.
Both PRs are merged to master. If you can, please give it a try. By the end of this week or early next week we are going to release 1.5-beta-1 and that should have these fixes as well.