In Mendix Cloud v4 there is a Metrics page where you can monitor running processes and even check the specific action where a process is. Then you could find out if it’s a rest call, a commit, a java action, a retrieve or whatever that is the common culprit. Maybe you could check, with Mx Support if necessary, if Azure offers a similar function. When you find out more, you could maybe start optimizing a retrieve etc. If it’s slow on a commit, you could remove indices. An index slows down committing, especially when a lot of users do the same thing simultaneously. And maybe you could execute some of the logic in a task queue, so users don’t have to wait for everything to be finished.
More on performance here.