I realize the October 17 deadline is coming up quick, so while my response isn't a perfect solution to your problem, it was intended to at least provide you with a resource (outside of Customer Support) to ask questions and brainstorm solutions with other Workfront admins prior to the transition date.
@jerflo Shared a few training materials below on the new Home workspace, one of which offers insight into the available filters for the My Work widget (see bottom of the page). If you have questions around Priorities or specific feature-function, Customer Support is free and available 24/7 to answer any questions you have around the technical how-to's.
The new Home workspace has been available for over a year now, so if this is your first time checking it out, then I agree it can be a little overwhelming as it's a new look and feel. In the future, I'd recommend staying on top of Product Releases so you are at least familiar with what new features are being rolled out, even if they aren't applicable to you just yet.
As for your reporting-related questions, there is a Best Practices - Dashboards article available on Experience League, and the blog, Manage Your Team's Work Using Dashboards, has great examples and step-by-step report creation instructions. If you aren't familiar with conditional formatting, you can add highlighting to a specific column (ex: late tasks) by adding a rule via the Advanced Options menu on the column itself. In your case, it would be if the Planned Completion Date > Less Than > $$TODAY on a task report.

When it comes to Proof reporting and missed approvals, there is a Proof Approval report type that can be customized to fit your needs.
If you have further questions, my team is happy to help. Our focus is more on strategy vs technical how-to's, so feel free to send us an email at csatscale@adobe.com and we can offer additional guidance, resources, and recommendations.