How my army works

This analysis is going off of my previous list with a few tweaks. Here, I'll be going over my general mindset when playing this list and what strategies I roll out with it.
The list involves Renegades from Imperial armor 5. Siege of Vraks reprint, Orks, Chaos Daemons, and Cypher's dataslate.

Okay, to start this off, I'm using The Purge detachment which forces me take elites instead of compulsory troops, i have no fast atrack slots, 4 heavy, 6 elite and 8 troop. This particular detachment also affects all of my barrage weapons with the blast special rule, and makes it so the blast templates stay on the field for a turn and count as dangerous terrain. I also took the Ordnance Tyrant devotion on my Arch Demagogue to allow me to take Renegade field artillery as non-compulsory troops and a whole bunch of other options from my heavy section gets moved to elites. As an additional bonus, my field artillery can fire onto my own dudes as long as the hole in the blast marker is in an enemy. AND i can fire into close combat (so it says. Im unsure if that means I can target enemy units in close combat, or it just means I can graze my own guys even if they are in combat.)
For HQs I have:
Renegade command squad with the ordnance tyrant upgrade and an Autocannon. Pretty strait forward on this part.
Elites:
Two units of Desciples, each with just an Autocannon leaving 3 bodies to just sit in front and soak bullets for the gunners, also not unusual.
In troops I have five units of field artillery with two guns ,each being the heavy quad mortars. Giving me a total of 10 of my favorite guns ever. The reason being is that even though I "can" fire into my own guys in close combat, I don't want a large group of my guns tied up in combat, getting slaughtered, when I can just spread them out in smaller chunks and keep everyone else shooting, thus, negating what I call the back line cascade, where all the important stuff is tied in close combat getting mulched, with the rest of my army just watching in horror unable to do anything because a key asset was in that assaulted squad.
That about sums it up for my Primary detachment, now onto Daemons:
For HQ I have Two heralds of Tzeentch on discs at mastery level 3. Their entire purpose in life is to cruise around the midfield summoning a bunch of dudes to just flood that area, give me support where needed, and grabbing midfield objectives.
For the mandatory troops, i just bring a unit of Nurglings. They're cheap, and with their infiltrate and shrouded rules, i just park them in a pices of terrain near an objective and just have them glom onto it and never let go.
This brings me to orks. I bring two ork detachments that are exactly alike so ill just go over what is brought and just apply things to both.
For HQ, I just bring the cheap little mek boy. He doesn't do much, but he doesn't need to.
Orky Troops get me a unit of minimum grots. Surprisingly, they actually help me out. They give me more bodies to flood the field with, block shots into my more important stuff, and can speed bump a unit for a turn or two.
The main reason I brought orks, however, is for tue lootas. I bring in a squad of 6.
Why go to all the troubke of bringing orks just for the lootas? Because with 6 lootas I'm having the same amount of shots from a support squad, 1/3 of the time and more often than not, twice or three times as many shots for roughly the same price as 6 guaranteed Autocannon shots. Plus the grots give me more wounds on the table that my opponent has to mop up.
Cypher's dataslate gives me my infiltrating chosen that have worked so well for me. I load them up with 4 Meltaguns and a combi melta on the champion, and have them go to town popping heavy transports and critical tanks that my Autocannons or lootas can't touch easily. Anything to slow the roll of my opponent.
To put it all together:
When placing objectives, I will generally place two, if not all three of them somewhere inside my deployment area, with maybe the one I don't, being put somewhere in cover for the Nurglings to grab and hold forever. This gives me the pesce of mind to know that half of the objectives are already secured by me and I won't have to worry too much about them going anywhere.
I deploy all of my artillery units kind of spaced out, with some of the spare crew bodies covering my Desciples in case my opponent is going first or steals the initiative. They are generally placed next to my backfield objectives because T7 makes it very hard for them to go away from anything other than close combat or Destroyer weapons. Desciple heavy weapons teams and my renegade command squad, are put where you would expect them to be: in cover with line of sight to something on the enemy side of the board.
The Arch Demagogue joins a unit of artillery that is in the middle of my field, so he benefits from majority toughness 7 and because his special rule that lets me fire with the template covering my own guys, is a bubble of 12 inches all around him, this positioning gives him the most bang for his buck and goes that extra mile.
Lootas set up in cover and fire away at light transports or high toughness models that pose a threat. I usually like to keep them on some kind of leveled ruin or something similar so they have the clearest line of sight. The gretchin mobs are set up directly in front of my artillery lines so they actually have a save of some sort in the form of shooting through a unit for a 5+. Mek boys just hang out in front of the lootas for an extra wound.
The heralds of Tzeentch deploy on either side of my board side, to maximize coverage, and roll every power possible on Maelific Daemonology. On my first psychic phase, they usually try to bring iut a unit of horrors, who also roll on maelific, to add to the warp charge pool, and in very lucky cases, turn into a keeper of secrets. If one of my heralds was lucky enough to roll the "sacrifice" power, which lets me bring out another herald for the price of a wound, I will either plbring iut another herald of Tzeentch with a mastery level 2 upgrade, Iraq a herald of Slaanesh for the charriot that does d6 hammer of wrath hits for each hull point left. Summoning daemons is all about using them like a proverbial scalpel: to precisely use this tool to carry out a specific purpose. If you try to use them just to make more things without an end goal in mind, then you're just wasting everyone's time, including your own.
Cypher and his chosen buddies infiltrate as close as possible to key vehicles, so when they pop the metal boxes, my artillery has more targets to shoot at. Sometimes it's best to not infiltrate everything and to maybe leave a squad of chosen in reserves because of imminent drop pods or something similar. In that case, if my opponent has at least something on their side of the field, I will infiltrate cypher with a unit if chosen into some kind of cover because he gives them all shrouded. As an added bonus, if the chosen and Cypher get tarpitted before being able to bring anything down, hit and run with initiative 8 helps my guys run away to take care of more important stuff.

(It's been mentioned to me that I should consider taking out a few the field artillery units and see how the rest of my army performs without them. I feel that that would probably be good, so i can actually see how my army does in late game since, every time I field this, the battle is over before the end of turn 2.)

Basically, my army three has pieces to itself: the backfield gunline, the midfield reinforcements, and the infiltrating tank murderers. In the few games ive played with this flavor of list, I have found that my opponents get tunnel vision on my artillery and forget about literally everything else I have on the board.
To that effect, I chew up my opponent as much as possible on my turns to make their resistance as futile as possible, which actually turns out fairly well with all the shelling going on. The heralds dump out more models, and in the case of a large assault unit making its way towards my back lines, I make some new daemons to bubble wrap my opponent. For this, I usually summon some daemonettes because of their running d6+3 inches to get into place. This one time, I had an ork warboss with a bunch of bikers barreling down onto me. I summoned two units of daemonettes, and each unit ran and spread out completely encircling the orks so in their turn, they could only shoot at one unit and be forced to charge it instead of going anywhere near my back lines, buying me an extra turn to retaliate. All the while my horrors were sitting on an objective scoring me some points, my gunline finished off the other orks, and my heralds kept summoning out more tarpit.