No one has told you to give up, tbf most on here would say well done for peservereing,
I've been in a similar situation as you.
When I started people gave me a lot of stick because I was pretty clueless about basic practical wiring, I'd never done it or been shown how.
I was good on the regs and theory but at that point it was difficult relating things to make sense, also I got shown and told stuff which was utter crap!
I used to ask a question then check the answer and slowly your knowledge will build up, and before long you'll leave these muppets behind.
The firm your with now just see you as a pair of hands, but you can use them to your advantage too by doing what I said before, this way you'll be reading how to do things correctly even if they don't do things this way , but keep your own standards higher and it'll come together
Ps re rods for domestic/small installations personally I run 16/10mm to the rod as you've described and bang in the 5/8 screw together rods down in as far as the ground permits and test it to see what reading you are getting
I keep on putting them down to get a reading below 15ohms although I wouldn't lose sleep if the best it could get to was 50ohms the most I've done this way was 14 down which gave me a reading of 3 ohms
If the ground is hard you may have to install joined rods in other positions and link with the earth cable basically building up a network of rods spread out which increases the surface area , giving a low reading
If there is rock close to the surface this will be best done by digging out an area of soil and taking the wire to an earth mat (basically a copper mesh) there are other methods mentioned in this thread also