Acces Data when Player is not in Game

I scripted a Login Page in Roblox, the Email/UserName and Passwort is stored in the Players Data, could i enter the Game with another Account and acces the Data from the other Player, like the Passwort and Email and have access to the Data when login success?

Just save the username and password data inside a datastore and when another account logs in, just check if the username and password’s data is the same as the one inside the datastore.

But is the Data saved inside the Player or inside the Game?

Data is saved inside a DataStore using DataStoreService