I feel like people whining about this being a no-tension "fake-out" haven't been reading the story.
Yeah, no shit he can come back from this, the question is if he comes back as Denji, and if so how many times he can come back until he starts to lose his grip and reverts into the chainsaw man Makima wants him to be.
It's probably gonna end up being a battle of his will versus her shitload of extra lives. Yeah, seeing one big dramatic death happen doesn't hold any permanence, but if you think that we're supposed to believe it does then I don't know what manga you've been reading 'cuz it ain't this one.
I understand other people being upset 'cuz we're at the climax and you want a resolution and it just seems to be dragging on, but big chapter(s)-long fistfight scenes are always great in the long-term once all the chapters are out and you can binge or re-read it. I don't fault the mangaka for wanting to make it big and dramatic. If you can't take the wait you're honestly best off ignoring this manga until you see a chapter pop up with the end tag, soak it all up at once with no cliffhangers.
Worst case scenario the ending is shit, still gonna be a better read than Fire Punch was.