A different job to be done
The two products solve different problems. Duolingo lowers the friction of starting a language; Lectura lowers the friction of continuing into meaningful reading. Many learners will use a course app first and then add Lectura when they want more comprehensible input.
What reading practice needs
Reading improves when the text is understandable, interesting, and long enough to create flow. Lectura optimizes for that by keeping the topic authentic while adapting the language level. That is different from answering many short prompts correctly.
Best workflow
Keep Duolingo for quick review if you enjoy it. Add Lectura for ten to twenty minutes of article reading, especially when your goal is vocabulary growth through context.