Most cold brew recipes online say 1:8 coffee to water, 12 hours. That produces something that tastes like coffee-flavoured pond. It is what almost every cafe serves. If you have written off cold brew based on this, I understand, but the actual ratio for a concentrate you would want to drink is much stronger than that.
My recipe: 1:5 by weight, medium-coarse grind, 18 hours in the fridge, filtered through paper. That produces a concentrate you dilute 1:1 or 1:2 with water or milk depending on how strong you want it. The 18 hours is important — short brew times leave you with muted, one-note coffee. The paper filter is important — a metal mesh alone leaves oils and silt that will taste heavy the next day.
Beans matter less than most people think for cold brew. A cheaper medium roast will actually give you a better result than a light roast — the cold water does not extract acidity efficiently, so bright beans end up flat. Save your good beans for hot brewing and pour-over. Cold brew is where you can get 90% of the pleasure for 50% of the bean cost, if you accept that it is a different drink from iced pour-over, not a lazy version of it.