Remember that your Titan keeps its XP even when it dies.

Suicide it against this fleet and take down as much as possible for XP then rebuild to repeat. Also, maybe build more bombers as well.

As a Loyalist you should be able to fortify your planets with 2 starbases each. Additionally they are highly durable. So try to place two in those wells they can jump in to, get them all armor and Security Protocol Override. Then jump in their system and shoot away at all that he's left. Should your starbases prove inable to survive his onslaught use Security Protocol Override on both of them (at 50% hull points, e.g.) and kill his fleet with it.

The rest is just cleaning up. 

I would vote for the Loyalist since they are more zealous than the rebels. That is if zealous equals vengeful and doesn't equal pious and peaceful. Besides, vengeful and pious both do explode nicely after Security Protocol Override. So this is more of an academic interest I reckon.

Usually tastes the sweetest this way.

Well, with the capital ships on full defensive abilities (health, shield regen, whatever), i could hold them off for long enough to get my two starbases out, upgrade their health, then their fighters, then their lasers. It worked quite well, I have to say.