This is not a direct feature of the plugin. However, I do have a tutorial for subscribers on the premium support site on how to remove sidebar widgets and leave the WP-Members login widget:
https://rocketgeek.com/tips-and-tricks/remove-all-widgets-except-the-wp-members-login-from-the-sidebar/
Also, there is a premium extension for the plugin – Advanced Options – that has a couple of different settings for removing widgets. It can remove all widgets except the WP-Members login widget if the user is not logged in, or there is a similar setting that does that but only if the page/post being viewed is blocked.
https://rocketgeek.com/plugins/wp-members/extensions/advanced-options/