I published a new blog post where I discuss how to handle async logic in a maintainable way. https://blog.mansystems.com/mendix-design-patterns-callback Let me know below, if you would like me to continue writing or if you have any feedback. You can also message me directly. I apologize for using the Q&A board for self-promotion.
Nice post Andrej. Actually found it interesting to see and would love to see more implementations like these with descriptions of how and why they are good or bad.