Is a speculative application worth it?

Yes — especially with preferred employers. A well-researched speculative application with a concrete value proposition has a significantly higher success rate than you might think, because you have no competition. Prerequisites: a clear offer ('I can solve X because...'), addressed to a specific person (not 'Dear Sir or Madam'), research into the company's pain points. Best industries for this: startups, Mittelstand, consulting-adjacent service providers.