I don't think you suck tho. Maybe you just haven't stumbled upon the right strategy?
And nothing clicks with everyone. Some just find certain systems harder than others. :)
I sold everything not needed for ammo (kept different amount of stacks depending on what I used most). If I needed a machine part for trading I just went and got a new one. You can also buy parts.
I'm about 30 hours in, and so far the difficulty has been about perfect. Sometimes I get in over my head and get killed, but for the most part, if I plan things out a bit I can clear everything. Not too easy, but not too difficult.
Now if you really want to talk about what was difficult in Horizon, talk to me about managing resources. How the hell does everybody else manage this without having anxiety? I never know if I should hang on to stuff in case I meet a vendor that wants it, or if I should be selling certain useless things (I figured out to sell the ones that are only for shards of course)?
I've upgraded my carrying capacity to the max (100), and it's not enough. I wish there was a stash or something.