What I would do is get rid of the Completed boolean column, and replace it with an if-then-else column, configured along the lines that Jeff suggested. That is:
- If Last Completed is within Today, then true
- If Last Completed is empty, then null
- If Recurring is not checked, then true
Here is how that would look with your sample data:
And here is how the if-then-else column would look:
One important point is that when you use that column as a filter, do not test for true/false. Instead test for is checked/is not checked.