So yes and no, when using an actual mfe if there are different versions of the ngrx store you will have multiple instances

try and use the oldest possible version in order to support old repos.

when "faking it" you only have 1 store but each application is aware just the part they initiated.

unless you pass the actions/selectors to other applications.

if you want total separation you can pass the instance of the store to any other application and use it from inside as if its your own ( don't recommend this pattern, but this is works)