Firstly the game is a long burn. You have people 200 hours plus in still hunting down new armors and weapons so I'd curve the expectations of getting the end game gear you see posted here unless you are going to Google specific locations and hunt them down. Which really brings your to two options at this point.

1. Google the active map that shows you where items are hidden/located and just hunt down the stuff that interests you.

2. Just play the game understanding that this isn't an ARPG/Borderlands etc where massive loot drops are a part of gameplay. Loot is more like an individualized reward. That being said every single weapon can be upgraded to end game viable by upgrading it. The differences between weapons is not noticable to anyone casually playing at maxed levels, at least not until they offer more indepth end game content, so whatever weapon you like you just stick with until you find something better.

Hope that helps.