Some suggestions:
1. Look at cash fares and using your Ultimate Reward Points via the Chase portal. There have been some outstanding business class fares to Europe and more are likely to pop up until business travel resumes to anything like pre pandemic levels, which could be quite a while. With Ultimate Rewards you can use any airline so just look for the best fare and book through their portal. Your 744K Ultimate rewards should be worth at least $9,000 in airfare (and more if you have the Sapphire Reserve Card) so more than enough for round trip business class for 2 on the dates you want and the route you want even without a major sale. Also consider alternate airports, for example Edinburgh or Manchster for London, Milan or Venice for Rome, Brussels or Amsterdam for Paris etc. Frequently you can turn that into an added opportunity. You have to be flexible to maximize the value of Frequent Flyer miles/points.
2. I have seen AA Saver Business class fares at 57,500 per person each way in that time frame depending upon the date and destination so keep looking. You could transfer your Bonvoy points to AA, which wouldn’t give you enough because the transfer ratio is less than 1:1 but you could apply for any combination of Aviator and AA Personal and Business Cards for yourself and your wife. Each one of those cards typically offers 65,000 bonus miles right now, so if you do not have, and have not had those cards in the recent past there are some easy pickings there. Read the bonus offer carefully if you have had them in the past.
3. Like I said, successfully using FF points requires flexibility. Be more flexible on your requirements. Flying into one airport and out of another is good, gives you more flexibility. But be prepared to fly from DFW and change at an airport in the US or in Europe. Non stops from DFW to London, Paris or Rome are the least likely tickets to offer saver levels or great fares (for obvious reasons). But opening up to a layover either in the US or in Europe will open up your options hugely.