How to setup Server Profiles via webapi with Steam integration

Hi there

Im working on a project with steam subsystem and advanced sessions plugin.
I would like to store the player info (level, skilltree, etc.) on my server.

I’ve seen many videos how i can handle webapi calls with blueprint to achive this.
But in every scenario ive found, the api is either publicly available without login or they create theyre own small login system.

How can i login to my webapi via steam subsystem to ensure players cannot manipulate others player data or get thyere private information?

Is there a way for doing this in blueprint or do i have to use C++ to achtive this?

Thanks for any help