The most good ending is known as the Dan Salvato Letter ending. In which, it's hard to do but here are the steps:
One: Do a new game, like you would normally.
2: On this, when Sayori comes up to you, save the game. That save file will be important.
3:Do any route in the first chapter. Natsuki's, Yuri's, Sayori's, etc.. It doesn't care (Route is by choosing the most words of a character's in a poem, and choosing eery option that supports that character.)
4: Once you've gotten to the talk in which Monika alerts the player about Sayori not going to class (yk yk), save the game.
5: The save file on the 2nd step? Load it.
6: Do the route of any of the two remaining characters. Do the same steps as 4, and 5 (saving the game and then loading the first save file)
7: Lastly, after you loaded the save file and finished 2 routes of different characters, do the route of the last remaining character! And then, play normally like you would.
8: Done. Basically, do all the routes on the first chapter in a single playthrough. This gives you a good ending, or so. Tell me if it worked! If you didn't understand, search more on internet/youtube by looking up "Dan Salvato Letter Ending DDLC".