I drink instant coffee all the time. I can't really tell much of a difference between it and regular coffee. You put as much sugar and cream in your coffee as I do and you wouldn't be able to tell either.
Now cold-brewed is a totally different ballgame. The cold-brew process extracts more of the sweet components and less of the bitter. I can drink cold-brewed coffee black, while I can't stand hot coffee that way.
Cold-brew is super easy to make too, you just need some ground coffee, a couple big jars, a funnel, and some filters. I use a couple of well cleaned 64 oz mayo jars. Add 1 cup of ground coffee, fill completely with cool water, seal, then leave on the counter overnight. Next day, put a filter in the funnel & run the brewed coffee through into the second jar. This makes a concentrate that you can store in the fridge for a week or two. Dilute with cold water or milk when you want a drink, usually about 1:1.
Now if only someone would make a freeze-dried instant cold-brew...
Yeah, I drink cold brew exclusively now. Even in the winter