So i actually did play it to check myself, and some of those are cherry picked. Lets be honest the sex scene wee can discount those cause thats just typical shit females say in avns LOL.
As for the rest, yes there are some similarities but there are enough differences. For once yes in both the MC gets pushed into a trap, but after the trap there are differences. (actually quite a few during that part). Also the "chief" is referenced differently in both. While im not discrediting the similarities, (and theres a chance that it was either taken from it OR inspiration from it) but there are quite a few differences too. I didnt scan everything worth for word, but the whole eb and flow seems a bit different in both. But who knows.
Maybe the dev just needed some bits and pieces to use to fill in the gaps and those gaps are what is being used to say its stolen? or maybe it is hard to say without going word for word script by script, and i honestly dont have the patience for that myself. But yea
One main difference i spotted in my quick shuffle through the text, is that when you go to the "pleasure temple" in both it is different. You get to choose to either be submissive or dominante, or both. In Nephilim i think its more you can choose to either be alone, with someone, or not at all.
Edit: After really looking at that screenshot and thinking about it its heavily cherrypicked.
The dragged and darted scenes: They are tribal they are going to use stuff like darts and stuff to nock people out thats a given.
Wake up scenes: Mc in Lust City talks about being in chains MC in Nephilim has chain and ball attached not chains.
Scene showing chief telling them to leave: Okay how much differently could they say to leave LOL.
Lost city reference: Okay?? that one is copy but lets be honest, if in both cases its a lost city, any outsider would call it "the lost city of x yz.