About Factions and Gear Score.

Hi Guys, just started to play Ghost Recon Breakpoint (actually I already have 100 hours) , I have finished the story and the dlc Deep State, I also have done the raid and my level is stack around 260. Now, just to keep playing, I'm doing side and faction missions but I didn't understand how they work. I saw a lot a players talk about faction rewards and about the elite missions to increase the gear score but I'm not getting nothing of this, just keep dropping stuff at 250. I cannot even find nothing about the faction progression in game. Can you guys please explain me what I have to do? It's just a bug or I missed something? Thanks in advance.