Let me see if I've understood. You want to create a user interface that lets the user change some standard variables and have that saved then replayed next time the user reconnects to the UI?
If so, this is fairly easy with Node-RED. All you need to do is to make sure that whatever the user changes is sent back to the Node-RED server and saved there in a way that is replayed whenever a new connection is made to the URL for the ui.
Exactly how you will do that will depend on what you are using to build the UI so that is the next question. Given that you want comms back to Node-RED, you are likely to want to use Dashboard or one of the 3rd party ui's such as my own uibuilder.
If you do use uibuilder, there is an example on the WIKI that shows you how to build a simple cache which is what you want - just make sure that you are using persistent storage for the cache variable. With Dashboard, it has a built-in cache but it isn't persistent across Node-RED restarts. Also, with Dashboard, the cache is always common across all connected users/tabs. It would be possible to adapt the uibuilder cache example to use different caches for different users if you need to do that.