Indeed, sometimes de-escalation is followed by further escalation. By your implied metric, every ceasefire that wasn't permanent was a failure.

Sudentenland is the exception that makes the rule. Throughout history, most peace agreements have not been immediately violated by the "winning" side.

And this war won't end either, if neither side gives in.

That’s the thing about war—if it goes on long enough, it eventually ends, because one side is unable to continue it. And if it’s the aggressor, then that stops them from continuing their aggression.