When you are logged in and at the main page of the space, you should be able to click on the members tab on the top-right of the space to see all group members (and admins, teams, as well as "inherited" members from other groups/spaces)
It is also possible to customize the spaces (space administrators) to have a block showing all their members (like here). This is a custom view we developed for the Degrowth conference, but which can obviously be (re-)used for other ends.
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