Yes, the total number of people using the app are 25 in number, as I learnt during the user requirement convenes with the stakeholders. (It’s an enterprise application, for a niche audience)
As we have a time crunch, I planned to take on a minimum of 4 users (the same ones) for each of the research activities as they were difficult to reach out plus in a foreign location.
I agree to your point, if different users are considered for different research activities we can glean more information but not happening as planned.
Kindly suggest me if things can still be improvised as you see with your experience.