I play solo 99.9% of the time and felt like Xol was actually pretty easy... I felt Nokris was actually more of a challenge than Xol. And actually I found the Nascent Dawn 2/5 quest step where you have to kill the Psions that are trying to become flayers to be harder than both of those other encounters until I figured a strat out. I was on the verge of finding a fire team to get past that one. But hey, if you would rather take a fire team in then do it! No shame in having fun with the game and not having to stress out over any particular activity. It's doable solo and cake with a fire team for sure.