How to design an online learning module that is both engaging and easy to achieve for K-12 students?

Hello everyone,
I am developing an online learning module for K-12 students using the AEA Learning Online platform. The challenge is to combine 3 elements: (1) high interaction (e.g., discussion, dynamic exercises) – (2) easy to use for both teachers and students – (3) ensure students actually achieve learning outcomes (not just “click through”).
I would like to ask the community:

Who has successfully designed such a module? What specific strategies have you used?

What obstacles have you encountered during implementation (e.g., student drop-off time, interactive tools not working)?

Do you have any tools or templates (e.g., design checklists, outcome assessment tables, interactive activities) that you would be willing to share?
I would love to hear feedback and real-world experience from those of you who have already done it, so I can improve my module to make it more engaging and effective. Thanks in advance for all your input!
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