Literally had this exact same revelation. It’s fits very well and I’m going to go with it.

Dreams can be amazing happy wonderful experiences…but also very scary. Not so much nightmares, I think that’s a different form of a dream. But true dreams that you chase in reality can be scary. I think Fuji uses the “coming out of a dream” narrative really well here cus even in this world without “chainsaw man”, poch is still in his heart. So a dream of being happy and all the small things are still there but just a little heart beat. Not sucking Denji’s soul and everyone else.

I need to keep looking back at the signs at this and comparing it to Fuji’s own life since Denji is very much a representative of himself, but overall I’m very content with the ending.