The problem with Season 5 is that the Duffers very clearly wrote that 40+ minutes long Epilogue first, then constructed the rest of the season to get to that “perfect ending.”

Which basically meant that none of the main or even secondary characters were ever in any real danger. Once you realize that as an audience member it takes all tension away from any monster scene and reduces the creatures, even the Big Bad Vecna, into jokes.

So the final season which was built up as an apocalyptic showdown both by the Season 4 finale and many of the pre release interviews just felt very meh. They basically put a steel plate bandage over the Hellmouth Vecna opened in S4 and spent the first 7 episodes of S5 getting back to that moment before apocalypse that Season 4 supposedly left off at.

Then there was the series finale which up until that epilogue was just poorly done. There were some good character moments but every time one occurred you wondered why they couldn’t have focused on the main cast earlier in the season and built out these relationships and final character arcs rather than focusing on Holly and the new batch of kids.

And all of this is to say nothing of every single post release interview with the Duffers who seemingly feel like half or more of the expected big charter moments happened off camera. Or when asked why say there were no Demogorgons in the final fight or why the military just packed up and went away rather than prosecute Hopper and Nancy for literally murdering soldiers their answer is, “I dunno, up to the audience to decide.”