Multiple stories in one online module?

I did something similar for a client (so I can't share it), but we used an overall structure of a frame story with two characters. One was a mentor, and one was new in their role (similar to the audience). These characters were advisors who helped students, and each module had 2-3 short student case studies.

Using multiple short case studies allowed us to show how to solve a wider range of problems, with more diverse examples. Having the two characters who helped solve the problems gave the modules a sense of continuity. That was important over the case of multiple modules totaling several hours of elearning.

However, if you're creating a single module, and it's not very long, the question of continuity might not be important in your case. Also, maybe it doesn't make sense to have connected characters for your case studies.

It would be cool to have some separate case studies that don't immediately appear to be connected, but actually have some relationship (I'm thinking of the opening of This Is Us, where you meet all the characters without knowing their connections).

Using multiple short scenarios is absolutely a viable strategy.