On Hammer and Anvil: Now, that's what I'm talking about; it was a bit less than totally perfect, but it was a waaaaaay more efficient battle and you did split the enemy and destroy their lines very well.
For the loss of a single Frigate (and that was largely a fluke) and serious damage to a Destroyer (not a fluke, read further down) you took out a force that had you outweighed in Cruisers and Destroyers. Excellent.
A couple of things I want to note, because if you review, you'll see them too.
1. Note how your Venture with the Railguns was as effective, if not better, than the Venture with the Heavy ACs, because it's quite a bit more efficient (it and the Light Needler are quite OP).
I'm still not certain that's a great loadout for Ventures, but it was massively more effective to use them to Flux-lock for missile kills than using them with Heavy Maulers; I think you'll agree if you watch what they did closely.
2. It's unclear what killed that Frigate, but chances are, it was killed by a chance lucky missile strike. You cannot always prevent such losses, but it certainly didn't die in vain. However, that might mean that a bit more anti-missile support might be warranted, if you want to take on late-game Pirates or Deserter fleets successfully. I feel like you rely on missiles a lot, and that works well up until you start meeting things that counter them well-enough that it's a waste of your OPs. More on that below when I talk about the Copernic.
3. I have no idea what mod-weapon that Mule is carrying, but that's a winner; it looks like a HE version of a Phase Lance, but with enough range to be actually useful. If you ever choose to get a Falcon, that might be a good choice. I wouldn't mount it on the Ventures, though, because I'm afraid it'd out-range the Railguns / Needlers / Heavy ACs, and cause the Ventures to waste Flux with pointless Beam damage, rather than opportunistically sniping Armor like the Mule did.
On Chaotic Conditions: I thought that actually went rather nicely, personally. Your frigate swarm efficiently cleared the trash and your anvil maneuver mid-fight worked well.
Note how effective that group of Shepherds was, too- that bit where they helped Flux-lock and kill that marauding Sunder made them worth every penny spent outfitting them well, and none of them got seriously injured.
How could this have gone better? Perhaps the biggest answer is that if you'd had strike-craft on your Condor (and, preferably, two of them) then you could've waited to deploy them until the Legion had made its presence felt and was largely Flux-locked (i.e., the moment the Ventures got into engagement range). This is a tricky waiting-game, but it would've paid off; four Wings of bombers would've put so much pressure on its shields that it would've been taken down a bit more rapidly, which might have gotten things wrapped up quickly.
Overall though, your grasp of tactics is obviously improving and your ship designs are a bit better. A few minor things:
1. I don't play with the Copernic or any other modded stuff in my private build, lately, but it appears that the build your deploying has shield efficiency so low and its Flux Capacity is so poor that it cannot take a single Gauss hit; the AI repeatedly lowered shields rather than Overload when the Legion's Gauss fired.
That's less-than-ideal; it's also so poorly armored that it couldn't take more than one hit without taking Hull damage.
I'd strongly recommend that you put ITU on them, strip the missile launchers to pay for that, and give them Captains with the extended-range perk. I'd also recommend putting a LAG on the other Small Ballistic slot forward, so that they can kill trash and other Destroyers once they've Flux-locked them with their Needler / Railgun. They should never have Flux stats so weak that they cannot take an Eagle using three Gravitons for more than a moment, if possible; perhaps they need Hard Shields. I'm guessing that the Copernic is badly-balanced and simply doesn't have enough OPs to make it really optimal, but in general, if it cannot take shield hits against heavies, then it needs to stay out of range and have weapons that can clear Enforcers and Hammerheads with the help of the frigate swarm.
Overall, without seeing their stats, I'm not sold on them in your fleet; they stand out as weak ships that need 10-20 more OPs to be really decent at their job. But perhaps that's just Hull Mod choices or other things I can't see. Just bear in mind that a ship that can't shield is 100% going to take damage in serious battles, and the only way to avoid that is by having superior range and speed, not more weapons or stuff like Heavy Armor that will just slow it down (if using that, btw, I'd vote for Flux Conduits instead; cheaper, and your late-game problem with a ship like that is EMP swarms like Lightnings killing it long before it loses a point of hull).
2. The one big mistake I saw you make was in the issuing of some specific orders that ate your Command Points.
Keep in mind that, if a point is labeled to Defend, and you manually assign ships to it (using 1 CP), if they're then given an order to Engage / Eliminate, they will return to the Defend point when they're done killing whatever you want focused down. This is a feature of the RTS controls that I think is poorly understood; essentially, Engage / Eliminate gets first priority, but if there's another task to return to afterwards, then ships will return to it.
Secondly, unless you need something focus-killed to break a pack or change the dynamic, use movement orders to break a line with a concentration of your forces, rather than focusing. Focusing is extremely useful when you can be assured that you'll get local superiority of forces and the target is too slow to get away (e.g., what happened to that Legion). It's not so great when you want your small ships to successfully clear the enemy's trash.
3. You called whether or not to fight out the end correctly, but that was probably the biggest nail-biter of that fight. I was afraid that Enforcer would get lucky and kill a Kite or two. Usually, if I'm in any doubt, I choose to Pursue and take the enemy down during the chase. I realize that you had an exhausted fleet with poor CR; perhaps as you keep playing, you'll have some "chaser" force, with a couple of leveled Captains, that has fast Frigates or Destroyers capable of winning most Pursuit scenarios after your main fleet has finished. I usually get ahold of a couple of Tempests that are only used this way (because of their speed and the terrifying mess Terminator drones make of engines on fleeing enemies).
4. Given that you're pretty much using the same two groups for Hammer and Anvil tactics each time, you might want to consider using the Control Group command.
This is a lamentably undocumented, unexplained feature of SS that only a few of us vets appear to know about; you can shift-click on ships, then hit CTRL + a number on your keyboard, and those ships are forever assigned to that control group. They will keep that assignment battle after battle and you can simply hit, for example, the 1 key and grab all your "big ships with Venture" group to give it orders. Saves a ton of fiddling-around time.
5. I know that this may be immersion-breaking, but by hitting the space bar, you can pause while in the Tactical Display. I do so constantly in serious fights, so that I can check my ships' status and the enemy's status before deciding whether to spend a CP. I think you wasted at least one CP in that fight (near the end, when issuing the Assault command or simply canceling your waypoints would've been more efficient) but mainly, I felt like you were occasionally losing focus due to not pausing to take a look.
All that critique aside, though, you're getting a lot better!