Colonia? That narrows it down a bit. Unless you can find one of the rare offers or a ship selling carrier, Jaques has pretty much the widest range of ships available. TolaGarf in Kojeara is worth looking into for the bits he's missing.
That can get you
- Vulture
- Fer-de-Lance/Mamba
- either of the Kraits
in sequence of decreasing handling and increasing hitting power
Loadout choices also can be limited, especially for larger items, in Colonia - and class 3 frags are currently bugged.
But you said you could engineer, and I'm just assuming that by now the Colonia engineers can provide (or surpass) all the services of the Bubble engineers. I also assume you have no access to Guardian goodies or Powerplay weapons. So I'd still suggest a Vulture with fixed guns and engineered thrusters. The Vulture has two main shortcomings:
- power plant: since engineering, this has become a non-issue. Especially since "armoured" would also give you an increase in power rating. With a bit of care in the remaining modules, you can run any guns you want
- canopy. When (not if) your shields fail, NPCs will invariably shoot missiles at your canopy, which will break. Therefore, I still recommend to run the Vulture with an A-rated life support and two point defenses on the shoulder position (top left and right, just below the guns) to attempt to take out those missiles coming in from the front.
The nonexistant jump range is typical for all pure combat ships - you can get the Kraits to do both jumping and fighting, but you'll lose out on agility then. Engineering the FSD will help a bit, but then again, Colona systems are more closely packed than Bubble systems.
I've put in plasmas just to see if it works, but (long range or whatever) beam lasers will also fit within the power budget (just, if you're using beams, use thermal vent as secondary):
https://s.orbis.zone/iwkj
You should be able to pick up everything somewhere in the Colonia region - just not everything in a single place. Apart from the above couple of stations, Colonia Hub (in Colonia) is a good address for outfitting.