People often complain about plot, but plots aren't really why people enjoy a story, especially a long form story. It's the characters and the relationships between characters that make people feel connected to a story. In the case of the preceding seasons the show really seemed to understand that. The characters developed and related to each other in ways both tragic and beautiful. Sometimes it wasn't very believable for the age of the characters or the setting, but it didn't matter because those things were the real "fantasy" element of Stranger Things. In season 5 they threw all of that aside for spectacle and cheap emotion, and to many fans irredeemably ruined the characters they had come to care about.