Drive to CVG and depart on a Mon-Wed and return the following week on Tue-Thu and you can get business in both directions for $3185. This is a fare rule requirement for the cheapest UA business fares (P2XNC79S) and very unlikely to change if you wait. You are basically excluding the cheapest fares by your choice of days for week for departure/return. As the days you have chosen tend to be more popular, the airlines exclude their cheapest fares from travel on those days. This is true for many European destinations.

Category 2: Day/Time restrictions
OUTBOUND - PERMITTED MON THROUGH WED ON EACH TRANSATLANTIC SECTOR.
INBOUND - PERMITTED TUE THROUGH THU ON EACH TRANSATLANTIC SECTOR.

Other requirements include a 60-day advance purchase and a Saturday night stay (which you already intend to meet). Both DL and AA have same business class fares with the same departure/return requirements, 60-day advance purchase, and Saturday night stay.