Seriously - I grew up working on Apollo where money was not a major factor! Alas facilities of those times are planned today!
If this was a period of plenty, and if we had the luxury of having a couple of Starliners similarly ready for launch, it would be an easy decision!
Bring the Test Starliner back uncrewed and study its performance and correct the anomaly of thrusters on the ground hardware. Test thrusters configurations in alternate uncrewed satellites and confirm that Problem is solved.
Then send the backup Test Starliner to bring back Suni and Butch.
This would enable an alternative US capability to SpaceX and can be done in about same time as Falcon return in Feb 2025 or so.
This would make use of 6+B invested in Boeing.
Let us not forget, over the years for Aerospace sector Boeing has Loads of useful information base, only they need to select correct people in their team who have the commitment beyond usual corporate goals related to bottom line!
These types of Logically then available Options (5 of them) were suggested by me to NASA on the day of Columbia Loss Feb 3 year 2003 and NASA accepted 3 of them for remaining 10 years of Shuttle flights. I had similar roles to play during Apollo 13 and corrections were made that I and my MSFEB team suggested for A14-A17 missions!
Best wishes to Suni and Butch and also for NASA investments in these crucial and needed technologies in support of Human Space Flight.
Ravi