shinyapps concurrent users in app


I have an app at server with free plan.
I want to have simultaneous users on my app and thereafter I would like to increase the "Max Worker Processes" at advanced settings under this app. Although when I try this, I cant save as I imagine that's not possible on free plan.

What are the consequences of having simultaneous users under the same working process? I saw that if a user closes the session, all sessions on the other users will also be closed.

i) The error of not be able to increase the number of "Max Worker Processes" is normal for the free plan?
ii) Is there a workaround to prevent the session to be closed among all users?