Should I apply cinnamon on broken phalaenopsis leaves?

[estación seca]

In a typical lower-humidity home environment, don't worry, and don't use cinnamon. The risk of fungal infection is minimal. The risk of root damage from stray cinnamon is much higher.

If you were growing in a high-humidity, wet greenhouse, it might make sense.

Your orchids will continue to grow normally. That damage isn't that bad. Really, don't worry.