Multiple Password protected pages

I have 12 separate pages on my website that are password protected for members only. It is a low-tech solution whereby the single password is changed monthly, and the new password promulgated to the members.

I understand how to set password protection on these pages, and that function works well, allowing access to ALL the protected pages once a viewer enters the password on one.

What I would like to resolve is how to change the one password monthly without having edit each of the 12 pages and manually change the password? (cumbersome and error prone).

I have seen one plugin that seems to do this, but notes show it hasn’t been updated in awhile and might not be safe to use.

Any guidance?