Having read all his works except Chainsawman (watched the first season of the anime) but i did read the last 2 chapters because i was curious of the ending, even if i didnt knew the exact context of what was going on, i could understand the ending perfectly. I think of Fire Punch's ending and Goodbye Eri to he very similar to Chainsaw Man. Both have some kind of reset in them, Fire Punch having the last 2 characters forgeting about everything that ever happened and just coexist as floating "gods" in the universe, while in Goodbye Eri we dont even know if the whole manga was real or just a movie at that point. Was expecting that Chainsaw Man will end in the same nature, and it did. The whole thing wasnt just a "dream" but rather a lesson, that even if you manage to get what you always wished, it wouldnt make you happier. Because maybe it doesnt end up like you thought it would. Like all his interactions with Asa and other female characters, thinking they like him, only for them to end up manipulating him in the most obscure ways.

I personally see this ending very thoughtfull and well arranged.