Probably a bit of an unpopular opinion but having not used a paragon in any recent version, I voted Conquest.
There is a very specific configuration which I have found seems to be capable of popping disgustingly large numbers of enemy ships on its own, and is well capable of holding two Onslaughts at bay when piloted with some skill (that's officered, real-world Onslaughts, not what-if sub-optimal simulator Onslaughts). The only drawbacks are range and that it has to relegate one side to PD.
So what are the main aspects that lead the build to success? Pressure and higher rate of fire weapons - this makes the conquest more independent and capable of standing alone against fighters and missile swarms, although Advanced Countermeasures 3 does help. Speaking of which, essential skills would be the typical gunnery implants, ordnance expertise, target analysis and missile specialization, though AC3 as mentioned before and helmsmanship do both help. You must use an aggressive officer unless piloting yourself as otherwise the ship will either cower and waste all of its missiles at too long range to fire anything else, or get itself popped by flying right into a deathball (with a reckless officer).
Weapons, face-wrecking side:
- Storm needler in the front large ballistic
- Devastator in the other one
- Heavy mortars in the mediums
This keeps the range of the weapons more or less equal and means the pilot won't hover outside of a range where they can use all of their weapons effectively.
Weapons, PD side:
- Mixture or exclusively Devastators or flaks, your choice
- Vulcans in the mediums
Weapons, the rest:
- PD lasers
- Ion beams - some much-needed long range support, but also good for pressuring and warding off unshielded frigates that try to get around your far side or rear
- Locusts - because obviously... Eats fighters for breakfast and is great for backing up the heavy mortars
- Sabot pods - a bit of a punch to back up the storm needler or use as a panic button in case of lesser mistakes
Hullmods etc.:
- Hardened Shields
- ITU
- ECCM
- Expanded missile racks, so the locusts last effectively forever and the sabot pods last longer
- Put the rest into vents
If you want to run it with Efficiency Overhaul or don't have Loadout Design 3 you can yeet the sabots pods for pilums and/or drop devastators to flaks. Obviously the latter is not ideal because you're losing the OP efficiency of not using HBI).
Damn near anything that approaches close enough to get hit by the heavy mortars will get flux locked in short order. The high flux dissipation and ion beams at that point often mean you can remain flux stable while turning the target steadily into dust. Fighter swarms coming your way? Doesn't matter! The locusts will take care of entire swarms on the way to the actual target, and anything that gets through has to brave the rest of the face-wrecking side.
It may not have the mobility of an Oddysey but I find you usually need to make some kind of sacrifice, and for me that ends up in underwhelming DPS even on locked down targets because I refuse to sacrifice anti-fighter capability by leaving the small energies empty. Odyssey definitely has an edge with the fighters though.