User Authentication and Management with Bubble.io and Xano

looking for guidance on the best approach for using an external database (Xano) to hold my user information. I am building the first app for our business on Bubble, but will likely use other platforms down the line to create native apps, admin pages, etc. I know how to connect the backend to Bubble through APIs, and how to get and use an authentication token. However, I'm having a hard time figuring out the best way to manage the various states/pathways (log-in, stay logged in, log out, sign-up) without using Bubble's user type database.