In hindsight of course that the GTVA could have done X and Y and Zed. What matters is what you can do within ten minutes, specially when you are being defeated by completely surprising technology like the beam jammer. Of course that if you had previous knowledge of this weapon you could have prepared against it and armed your ships with "tag missiles". But you didn't because you were caught with your pants down.
To have a sudden cruiser just come out of nothing with TAG missiles ready within just 5 minutes of the Serkr team being surprised would be a completely irrealistic plot. No army is able to think and execute a reaction that fast.
Yet one of them single handedly wiped the floor with the Wargods.
This is utterly ridiculous. The imperieuse won that war because the wargods were already pressed with the Carthage and its escort, and by the surprise effect. You cannot possibly believe that a single Titan is able to destroy four Karunas. Because it isn't.
Further, a Solaris and two Karunas will kick the Imperieuse's ass in less than one minute. (Not that my own experiment was a good one, since I didn't get the ****ing Titan to open beam fire, but still it was an eye opener)