Buffy fans, I need your take on this!

So, I just finished watching Season 6 episode 17, "Normal Again", and the ending caught me by surprise. I thought they were gonna end the "Buffy being interned world" when she saved her friends from that demon, but the fact that she's still there at the end left me so confused. Is Buffy interned in a mental institution and the whole show is just her imagination?

I did some research and some people think both worlds are real, like some AU (alternative universe). Also, I found that Joss Whedon said the Slayer world is real, but that he wanted to leave the ending of the episode to open interpretation, which is food for thought. I personally feel relieved that the Slayer world is real, cause imagine watching 6 seasons and then "hey, none of it was real, have a nice day!" 😅

But I wanted to ask you, what do you think about the idea of an alternative universe with Buffy actually being in a mental institution? Or the whole episode itself? I'd really love to read your opinions!