so Im gonna leave it uploading & go to bed. Its at 10% rn, just gonna drop the link now https://www.mediafire.com/file/3vlygjsmghowj0p/test_save.7z/file
So out of curiosity, I downloaded the save. That's quite the mod collection you've got running.
So, your cruiser officer looks to be cautious and has been given a converted fighter bay? My guess is it is using cautious carrier AI, although I'm not positive if a single bay will switch over to carrier AI. Generally a cautious carrier stays way back, since its fighters have a range of 4000 and cautious means stay at maximum range while having 1 weapon system in range. The S-mod expanded missile isn't doing much for the ship unfortunately, given it has only 1 Kneecapper MRM pod (which regenerates ammo like a salamander). The dedicated targeting unit s-mod does give your beams a range of 1500 on its all beam loadout (Graviton, Ion, 2x Tactical, 2x PD, 2x Mining), so that's helping some. Although, the ship is running 0 extra caps and only 3 extra vents and will slowly build up soft flux on itself. It exerts only 400 soft shield damage per second on a target, which to be honest is quite low for a cruiser.
The mercantile convoy you talk about has an expanded missile racks + integrated targeting unit equipped Venture with dual annihilator pods, dual annihilator launchers, and dual hypervelocity drivers. It's only d-mod is damaged flight deck. So flux free HE and 1600 range hard flux kinetics, plus ablative mining drones. Also 0.95 shield with 470 flux/second in vent capacity. There's a level 4 officer on the Venture (reliability engineering, helmsmanship, target analysis, elite gunnery implants) versus level 2 officer on the Fury (helmanship and strike commander). The skills are different from Vanilla so I'm not sure how that factors in. Also, I don't remember mining pods running that far away from the Venture, I mean like at least half a screen length away.
Given the escort destroyer is only equipped with PD and a salamander equivalent whose role is "Disabler", it wouldn't surprise me if it decides to escort your cruiser every engagement. Certainly in both pictures you show, the destroyer is very close to the cruiser. It does have an aggressive officer at least.
The Brawler is reckless, but equipped with 1000 range suppression weapons. At least in the first image, it looks like it was in fact engaging, so perhaps working as intended. But it's going to be staying pretty far away even when it does engage, simply because all it's weapon systems are long range.
The mod frigate (Hedone) is equipped with dual light machine guns and an aggressive officer, so it should be engaging (and was according to your screenshots).
The player is piloting a hammer torpedo + pd weapon kite, so good strike while the missiles last (12 total with expanded missile racks + missile skill).
So I tried engaging the mercantile fleet as is.
The destroyer broke off and did in fact try to engage a Mule with a Torch and Hound. Problem was the Mule was equipped with 2 railguns, a heavy mauler, and ITU and thus severely out ranged the 600 range PD guns (1200 Heavy Mauler and 840 railguns). But it was trying at least. It would dive in, shoot, and then pull out because, well, it was losing the range war on the dive in.
Brawler was engaging 1 on 1 with a Heavy Blaster Wolf, but lacking hard flux damage, was losing that exchange off on the right.
The Fury looked like standard cautious officer behavior, and was backing off starting fairly early because of it's long range weapons and fighters. It destroyed a forward kite fairly early on. The Hedone was 1vs1 a Hound, but was definitely engaging, as expected of an aggressive officer and ended up at the top of the map.
Behavior looks roughly like what I'd expect given the officers involved. Your fleet's configuration essentially requires all your ships to focus fire on anything bigger than a Frigate because of the beam composition. Your fleet's hard flux shield damage is basically a time accelerated Yacht with 2x dual light machine guns, a converted hangar broadsword, and a converted hangar high tech talon (4 fighters with a dual light mg each)? Given the player is piloting the smallest ship, which basically only has 12 hammer torpedoes, there's very little long term player pressure available.
The Mercantile convoy is all long range and typically ITU boosted, is 85% CR to your 70% CR, and running rare weapons like railguns, hypervelocity drivers, heavy maulers and heavy blasters. The two Hounds have Hypervelocity drivers. The vigilance is running Graviton + Pilum. The wolf is packing a heavy blaster and sabots. One kite is strike it looks like, while the other is harrass (salamanders). It out numbers your fleet, generally out ranges your ships, and in the case of the Hounds, is roughly as fast. To be honest, if this were a purely AI tournament fight, I'd expect the Mercantile fleet to win.
Edit: I ran the fight one more time, and left the player kite to AI control (pressed u). Watching the overall fight rather than frantically piloting a torpedo frigate attempting to get a good shot, the Fury definitely seems to engage ships smaller than itself. So I might be wrong about the carrier AI. It will plasma burn in, but then back off, presumably trying to keep to its optimal 1000-1500 range or so. All the ships seemed to be fighting something the entire time. However, superior range and CR took it's toll ending with victory for the merchant fleet. Without player guided torpedos, the fleet just doesn't kill even frigates or destroyers fast (other than that Hedone - that thing is nasty while it's CR holds). Overall, it looked like ships were acting in accordance with their officer AI.
Edit 2: To offer a concrete suggestion, try swapping for a Reckless officer on the Fury (or edit it in the save file to change Quinn from cautious to reckless).