Boeing has apparently had some sort of capsule (+ service module) thruster problems on all of its StarLiner flights, so far. That does not bode well for NASA acceptance, even if there was no problem with this last return flight. Boeing needs to show that they have solved the problem, rather than NASA deciding to accept the risk that the consequences of the unsolved problem will be a major disaster at some point in a future mission.
Boeing is in big trouble on many fronts, even including a labor strike that forced the company to stop producing its most profitable product, which was already restricted in its production rate by the Federal Government to provide for Federal inspection oversight due to Boeings past failures to resolve its quality control issues.
The new Boeing CEO will have to decide whether it is worth the cost to fix the StarLiner to NASA's standards of reliability, or save the money but take the hit to their reputation, which needs some positives, not more negatives, at the moment.
And NASA may need to decide whether Boeing is "too big to let fail" so that it needs dollars of support even if the prospect of getting a useable product is unlikely. Congress may play a bigger role in that decision than NASA executives.