Since apparently I have Ideas™, imma write up some tech proposals.
"Casablanca"-type Fusion Shell: Explosively formed penetrator weapons are not unknown to the Mechanicus; generally the the weapons of the desperate, which is a fair assessment of the Lativa sector in general. The Casablanca is essentially an EFP writ large; a high-yield atomic weapon forming a relativistic jet of plasma out of a metallic plate. With the power of the Motive Force and AdMech mastery of physics, the Casablanca (in theory) should match or surpass current kinetic penetrator performance as well as increase effective range of our current macrobatteries due to the speed at which the plasma jet propagates. The shell must still be fired away from the ship in order to avoid damage from atomic detonation however, which may affect accuracy until gun crews can adjust to the initial "lag" between firing the shell and detonation. Archival data suggests that this style of weaponry originates as far back as M2, though analysts are still mystified by references to piano music in the data dumps.
-"Boggart" seeker head: If the Casablanca yields favorable results, tentative plans call for adding a seeker head and fuze that would aim the shell in flight and detonate at a more favorable proximity to the enemy, contributing to longer range and more accurate fire.
"Tachocline" Las macrocannon: Essentially a lascannon enormously scaled up, the "Tachocline" would be Calavar's first foray into captial scale laser weaponry. The simplicity of las weapons in general should lend itself to a reduced logistical footprint in reduced maintenance as well as no longer needing shells to be manufactured.
-"Blaze Lock" capacitor system: Should the Tachocline perform as expected, a capacitor system similar in function to Hotshot las power packs has been proposed to further increase firepower. Reinforced power feeds, increased cooling, and a lens more forgiving of heat warping may be required if the capacitor system increases yields beyond standard tolerances.
"Dragon's Teeth" Lance Torpedo: Inspired by the Ork's crude, if potent, "Zappas", the Dragon's Teeth torpedo utilizes an atomic warhead to power an array of expendable laser devices to generate a barrage of powerful x-ray lasers. In theory this subjects the target to a concentrated barrage of firepower, though whether that barrage is "merely" the equivalent of a storm of macrocannon shells or the equivalent of the armor shredding power of a Lance is dependent on how much the Admech can extrapolate from the Ork's haphazard designs. The Dragon's Teeth, should the design meet projected expectations, has the advantage of being able to hit a target beyond the effective range of most point defense batteries, however this means that the laser barrage can be blocked by Void shields and other energy screens that a standard torpedo would not be subject to.
Edit: changed the name of the las macrobattery.