It feels like a bathtub curve. Gets less funny as the gallows approach but picks back up when you're firmly in the noose and the only thing left is the humor and the ride.
That's not true. The difference is that terms that consist of two words in english (like "gallows humor") are a single word in german ("Galgenhumor"). But the sum of the letters is often comparable or can differ in either direction.
it's more about the fact that gallows humour doesn't become less funny when the noose is around your neck but that it's ONLY funny if the noose is around YOUR neck
anyone not in danger making jokes is just cruelty or bad taste and will never sit well with whoever the noose is going around