It's a kit thing. Extract brews are better, but all grain is the answer, if you make the effort to make an all grain brew you will be gob smacked. I wasted many years of my life doing kits or avoiding doing kits and then one day I bought some grain...
Why keep making something over and over and keep wondering about the twang? Ditch the twang! Get a stock pot and a mesh bag, and mash some grains, and then boil your wort with some lovely hops of your choosing.
If you can't be bothered to do that, at least make extract brews with dried extract and steep some grains like Crystal/Chocolate (any grains that don't need mashing), and boil with hops - you can experiment and find which grains and hops you like best - and which yeast too. It's a doddle. A monkey could do it.
If you lived in Preston and some rich bloke in Honolulu offered you a life swap, would you hang around in Preston? (sorry Preston folk!). Whenever I go in a homebrew shop I am struck every time by the realisation that most UK homebrewers just open a can whith no clear list of ingredients, pour it into a bucket with some water and give it a stir, before sprinkling some unknown yeast on the top. Wake up folks! It took me years for this to hit me. Don't be like me and waste the best years of your life on kits! To me now the majority of pub beer is rubbish. And for £3 I can buy the ingredients for about 15 (500ml) bottles of homebrew. Grain is cheap.