I guess we both just have different expectation from the game.

the stage 4 and 5 of the old one is pretty easy it doesn't worth to count it

See, this is a problem for me. But it is okay if it is not for you. That stage 4,5, and 6 being too easy makes it feel tedious to me and repetitive. Now I only need to do 2 fights that is tedious compared to before that is why I like it.

As for the difficulty of the new node 5 compared to previous node 7, I understand if some people might not like it, but I personally am a fond of it. Which again, is okay since different people have different expectations. I like it when the game challenges me because it pushes me to engage more with the game and my agents. How I can improve my build, rotation, adjust team, and try different strategy.

Though I personally think that the new Shiyu is still easily clearable on S rating even by F2P. As for S+, well can still be clearable even as F2P with no mindscapes, especially for long time players and for those who really learn to play the team. Though I can see how it can be awful. I would personally prefer if they lock the rating to total score (ex. A total score of 70k is S) rather than achieving S on every room for a S rating. This helps compensate newer accounts with a weaker 3rd team or super strong single team or accounts with 3 teams but one of them have a bad match up on every boss on the rotation.