Just like you, I would like to have temporary user assignments to memberships in my SP forums, for 1 month, 3 months or a year.
So far, I have not seen how to specify this in SP admin panels. Of course, I could use a spreadsheet to register the information, and every week perform a manual update of SP memberships. It’s obviously tedious.
I would like to be able to enter start date and end date of assignments when I assign a membership to a user.
Please tell me if it’s somewhere in the admin panels, in plugins, and also how you proceed for your own SP forums.