Keep in mind that these weapons are designed primarily for being at their best on Templar ships. Especially when the hostile Templar ships have 50% weapon flux reduction, every weapon is deadly. The idea is to make these weapons not automatically be the best in the game; while they should be really good and powerful on Templar ships, for everyone else they have pros and cons like every other weapon.
The Sentenia is best used as a general-purpose kills-everything cannon. It can't punch armor as well as a Heavy Blaster or Heavy Mauler, it can't kill fighters and drones as well as a Longinus, Heavy Burst Laser, or Dual Flak, it can't reach as far as a Hypervelocity Driver or Heavy Mauler, can't track as well as a Salamander Pod, etc. However, it can do all of those tasks, if not at the highest level, at least competently. It can punch through armor over time and deal some pretty nasty DPS, it can kill fighters and drones, it can reach pretty dang far, it can track around and hit targets that are trying to dodge, and more. Having such multipurpose use is why it works well on your Apogee, which needs to rely on them for most of its combat roles.