Personally, I feel like many people are upset with the ending because it leaves too much uncertainty. For example:
We don't know why GZY made the face he made at the end. We can't truly know what happened to YWS. She could be dead or she could be alive. We have no idea how many members of WuFeng are left. It's annoying. I would have been okay if we got to see her dead body and I think many other people would have too because it would offer closer. But we don't. Furthermore, her easily being lowered into a trap to go see her twin sister? I'm not saying HYS didn't write the letter or set up the trap for her, but if HYS knows about the sister, the logical conclusion should be that the WuFeng leaders do too, and will probably have her in their clutches. YWS is supposed to be smart so her not thinking about that and being shocked to see DZ and that one guard there is ridiculous tbh.
Lastly, SGQ's ending. What happened to the revenge she wanted so much? Idk, her just living peacefully after stating that she did all those things to avenge her family is weird to me. She spent all this time climbing up WuFeng ranks with the hopes of revenge just to give it all up? And the whole "I'm pregnant thing".
I'm not saying everyone needs to end up together and run off into the sunset but that ending was ridiculous in my opinion. I have a very STRONG hatred for open endings. They feel like lazy writing to me. It only makes sense to do it if a second season is guaranteed and in gjm's case, it was not.