1) I think the most immediate issue is weapon mis-grouping. Group 4 contains 2 Gravs and 2 TLs. Paragon keeps 'manually' firing TLs while only Gravs are in range.
...I can't think of any cases where 'manual' fire helps AI. It sure hurts with range mismanagement or when turret arcs don't converge (so only 1 side can fire, if AI starts to use group manually).
2) Next one is trying to keep distance from opponent that is built to snipe. Obviously this Paragon would have had much better chances in close combat.
3) It does intermittent flicker in exactly wrong way. Best option is to raise shield right before Gauss shots arrive and mini-vent right after, okay option is to tank with intermittent fortress shield then vent while armor tanking and repeat (it would still lose, but not nearly as quickly).
...I'm not sure this Paragon can smash said Onslaught in AI vs AI though. Onslaught gets decent advantage from fleetwide skills (most notably 9% range) and is built to counter the default Paragon with Gauss. You should really do your AI tests from missions, to remove unfair advantages.
Paragon could, in theory, use it meager speed advantage to approach, but at 30 vs 26 it would need to be much more committed to it than AI is capable of (or use zero flux boosted armor tanking approach, which is once again a tactic the AI doesn't know).