Curious if anyone has any ideas. This is difficult because you have to go up one level (task or issue) and then do a collection. So you are going up and down. Even with EXISTS filters, I've never seen anything that goes in both directions. Normally it is up (or down) but multiple levels. Fingers crossed.
We don't have hours/timesheets in our instance so I can't test. But you might want to try a task report and then use a prompt for Assignment Users ID. That filter will show all tasks assigned to that person whether they are task owner or not. On the Task report, you can then do a collection for an hour's object type's entry date. You can then do the same for issues.
Just a thought.