I've tried the same thing many times, but I still can't get that ending. Could it be because of the 5.5 update?
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I have not gotten the ending myself, but from what I’ve read, there are other choices you need to make to actually get this ending.
You have to choose all the negative options for the characters in the game, go to Ren’s apartment on day 4 and say you enjoy seeing it, and then on day 5 tell Ren to leave after you see his text.