Using the Multiplayer Account System (MADS) you are able to easily integrate the logic code to introduce accounts and characters on your project. This system are focus on authority(singleplayer or multiplayer) model where all data is handle.
This asset is fully in blueprints and don't need to use third-parties softwares or plugins to work. All persistent data is saved as local files(unreal savegames) on the authority side. You don't need to worry about data models design on infrastructure layer at this moment. If you desire to test/try your project with 5-10-20-30 players at same time, this numbers are too low to need a database server. You can focus on the game design and later on your production phase, you can easily modify the MADS to handle all data in your chosen database server.
This asset are very well commented, organized and easy to modify.
Notice: To be more clear, this asset aren't "Code Plugin" and don't come with a database connector or any database functions.
Some published examples that you can use: Microsoft SQL Integration, MySQL Integration.
On discord channel, I can try help you at this integration step but, I can't promise the third-party assets performance/functionality.
You will need this in the future, when desire to integrate your project to a database and reach a good performance with a lot more players or build a dedicated server from source.
Video
Migration
Discord
Playable Demo v.20230515 (MACS+MADS) - PS: MACS and MADS assets sold separately.