Hello,
Welcome to Microsoft Q&A!
For this scenario, we suggest your login the app with Windows Hello, you can implement this technology to protect their Universal Windows Platform (UWP) apps and backend services.
For syncing user name/password for the customer into a sqlite db please refer this code sample server part that use to store windows hello public key and user id.
Thank you.
If the answer is the right solution, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.