Good day from sunny Athens (Greece)
Have been playing ED for a while, mostly doing data delivery and scan jobs. Never did combat really.
Got myself a cobra mk3 and loaded with with some nice stuff. Now at Rhea 3 ring, low res and bounty hunting.
Any further advice on the load or minor ship upgrade would be appreciated (budget 8-9 mils max)
https://inara.cz/cmdr-fleet/78325/280706/
In this and every other game, you really should test out all your ships' available weapons and see how they feel for you.
But i'll still tell you how i personally equipped that ship, which i used for quite a while as my main combat ship and i'm still a big fan of...
Firstly, as a veteran of Egosoft's (unfortunately, PC only) X series, i really like high rate of fire weapons and missiles.
So multicannons were a pretty obvious choice for me as my main weapons (and i've used them as such on my Viper mark iv, Vulture and every other ship i've used in any sort of combat since, including the Diamonback and ASP Explorers etc) .
Multicannons, as well as being nice high rate of fire weapons, do nice damage, use a relatively small amount of power to run and don't build up the large amounts of heat some weapons in this game can.
Also the position of the class two slots on the Cobra, up on its' nose, let gimballed multicannons hit enemy targets easily.
While the Viper mark iv can be made a fair bit tougher than the Cobra (though it's slower and more sluggish than the Cobra), i ultimately replaced my Cobra with one as my main fighting ship and i'm only now testing out a Vulture, i dislike that the Vipers' class two weapon slots are underneath it, making it harder for the guns to hit targets.
As for the class one slots on the ship, which i dislike the fact that to use missiles in this game, you've to fit them in a weapon slot (as oppose to firing them independently of your main weapons, as in the X series and many other combat games, but i still HAVE to have missile launchers in my loadouts

.
I initially tried carrying missile launchers in both class one slots on the ship, alternating between firing both launchers together to increase damage or assigning them to different fire groups to lengthen the amount to time i had missiles to fire, but in the end, i decided to drop one launcher in favour of a third regular weapon and after trying out several other weapons, added a third multicannon to a slot.
Again, while it's annoying that using missiles in this game means giving up a regular weapon slot and how fast you can use them up, they're still great to use on ships when you knock out their shields, particularly if your target is in danger of getting away from you or it's looking like the local police will steal a kill off you

.
However if you want to maximise your longterm dps, you could just fit multicannons (or whatever other weapon you might decide you like better in all your weapon slots...

).
Again test out all the weapons you can find and afford and your ships' loadout will support, but i reckon my set up is still pretty good and possibly the most fun...

.
Edit:- Also, for combat, it's best to fit the best shields, shield boosters, as many hull and or module reinforcement modules as you can find, afford or fit in your ship (and in particular with shield boosters, as your ship has power to run) and to fit military bulkheads.
(You can worry about jump range outside of combat builds, though the pretty combat focused build i have on my maxed out Cobra can jump 20 light years unladen, 18 laden with military bulkheads and 22 light years unladen and 20 laden without military bulkheads, while still carrying 32 units of cargo

.)
If you want the maximum protection your ship will allow, you could strip your ships of even cargo ranks, discovery scanners, docking computers etc and fit reinforcement modules in every available slot, but while i indeed carry no cargo racks in my Viper and Vulture, i still keep a discovery scanner, docking computer and a Kill Warrant Scanner in my class one and two module slots - class one and two reinforcement modules don't add THAT much protection to you ships anyway, their not on the same level as class three and four reinforcement slots.
(Though i've even pulled out my discovery scanners once i settle into a combat zone.)
(If you've stripped all the cargo racks out of your ship, though i would save that sort of build for a Viper or Vulture etc, there's nothing to stop you equipping your Cobra with a pure combat loadout, while storing the modules you use for other tasks, turning off your ships' cargo hatch in your ships' right hud panel will give you a tiny bit more power to run weapons

.)
Also on the KWS, it's recommended to only use it on already wanted ships.
It can increase the amount you get paid for kills significantly, while it can also earn you rep in other sectors to the one you're currently in.
(While you CAN use the KWS on a ship that's clean in your current sector, revealing its' possible wanted status in other sectors, but since as far as the local authorities in the sector you're in are concerned, it never stopped being an innocent ship, so it's an offence to attack and or kill it and doing so would earn you a wanted status...

.)
Lastly on your budget, you should be able to max out the Cobra for six to seven million (including the cost of buying the ship), so if you've eight or nine million now, you've loads!

.