So it's not really a matter of getting gud here, the issue is the latest gaming mechanics are designed to lead players towards engineers, obviously.
Uh, no. That's a trap. I mean, it's absolutely true that engineering is huge. It's a massive advantage in both offense and defense. It's way out of whack and by all means should get beaten to hell and back and for the sake of the game and it's health take some massive nerfing. But it's not the solution when you have problems with combat.
Whenever there's a new ship around, i first pick up the ship in non-engineered state. I put it through a number of personal tests. One of them is to go to RES and pick fights against targets of different sized and rank. So yes, any new ship which comes around ends up facing a number of elite ranked NPCs in ships of different sizes.
Last time i did this was when the Mamba and Krait Phantom were added, so not so long ago. (There were only minor bugfix patches since then. ) Usually i win those fights, only sometimes, when the ship doesn't suit my style, i mess up or try to bite off too much, i had to retreat. But i never yet lost a ship during one of those test runs.
So yes, non-engineered ships are at a massive disadvantage against engineered ships. High ranked (dangerous, deadly and elite) ranked NPCs do field a lot of engineered components. Fighting those in a non-engineered ships is no walk in the park.
But even now NPCs of lower ranks have little to no engineering done. If you struggle against those, the problem is not in engineering. You're fighting them on a level field. Your ship setup by itself, engineering or not, might be suboptimal. Also, while you say you are an experienced gamer, you're not a veteran of this game. So really, some training there might be necessary. There's a lot of tricks and quirks in this games flight model, damage calculation and other mechanics, which are rather obscure. Sometimes they even work contrary to all logic. A number of mechanics of this game are badly explained or completely hidden.
Thus i dare to say that this is where you actually should look at: learning all the hidden things of the game. It has a steep learning curve and it often is not intuitive. Some things which you bring along from other games and are of advantage there, turn out to be a disadvantage in this game.
It sure is easier to just engineer a ship. If your ship is just leagues above and beyond what NPCs fly, you sure can perform well. But it's really just a crutch and i'd advise to work your knowledge of the game instead.
Edit: Ah! Now i get it. This part gives it away, when i pay enough attention:
Sometimes I can't even turn 180 degrees before they vaporize me and they are between range 160.000-200.000 pirate lords.
You are running assassination missions? That's not the right place to start for learning combat and bounty hunting. I mean yes, the game leads you to those. But quite often you end up fighting a wing of enemies, which indeed results in quick destruction of a small and non-engineered ship. It's again one of the things which are not that obvious.
I rather advise to first go to your local nav beacon. Make sure that it is a normal nav beacon. If it says that it's compromised, go to another system and check the nav beacon there.
At this normal nav beacon, cruise around. Scan all ships you see. Look for those which are marked, are not in a wing and don't have a too high pilot rating. Start taking those down. As you are in a normal nav beacon, police might also be present and assist you, making the kills even easier.
Once you are confident enough with the nav beacon enemies (should be soon enough), you can move on to RES, wich means Ressource Extraction Sites. Those can be found at many planets with rings. At the start, avoid Hazardous Ressource Extraction Sites. Enter the other kind, again fly around, rack up kills.
Once familiar with that, you can try to go for the Hazardour Ressource Extraction Sites or Compromised Nav Beacons. There will be no police there to help you out, while you can expect to meet much harder enemies, bigger ships and higher rating (and thus some engineering done to their ships). On the positive, the bounties on them also are much higher, so the income is better.
And yes, all of that feels a bit more like policing than hunting a bounty. But it's how you really get some good combat time and thus practice. Once you're a bit more familiar with the game and the quirks of its flight model, you then can also look into assassination missions.
I hope this helps.