The latest update for the Samsung Galaxy S10 and Galaxy S10+ locked its users out, requiring them to enter a PIN and restarting repeatedly no matter what they entered. Unfortunately, it looks like performing a Factory data reset is the only solution available for those affected by this issue.
https://www.notebookcheck.net/Samsung-Galaxy-S10-and-S10-got-an-update-that-locks-users-out-randomly.427321.0.html