For the broader war, Beowulf could have easily delivered victory to the SLN. Manticore was having Beowulf rebuild their infrastructure and provide missiles! If the Mandarins were a little better at propaganda, not being morons and not being evil psychos they really should have been able to flip Beowulf after the little "oopsie" at Mesa.What if Beowulf had a change of heart and didn't like the trap the RMN had so neatly set and decided to flip its allegiance back towards its own founding and somehow assisted the SLN? Now, I don't know what form that could have taken which would have resulted in a victory for the SLN, but I'm sure with Beowulf's assistance (who the RMN trust implicitly) the SLN could have cost the RMN a lot of lives. Would that have been traitorous of Beowulf?
Of course, if that was the case they would have thrown Byng under the bus, and would have updated their training with a "How to respond to potential stealth attack" module. Also a "How to not turn off your wedge next to potential hostiles" module.
Now for the second Battle of Manticore, Beowulf would have had to have been particularly treacherous to turn the tide on that. Maybe surprise attack the Manticorian forces on Beowulf's side of the hyperbridge, call for help from Manticore, and capture the ships Manticore sends through. Then finish Manticore with its own fleet.
This reminds me: The Mandarins really should have been investing in brain transplant tech. Preferably with an automatic pocket sized surgeon. Then they could have body snatched their way into control of Beowulf!