My Google-fu has been failing me for roughly half a day now. I've got a basic ASP.NET Core web app that uses Azure B2C for authentication. Now I'm trying to update those users in B2C as the application itself, but I'm having trouble finding information on how to do that. I've seen pages that say I should look into the Microsoft Graph API, others that say I should use Azure AD API, some links that point me to adding an app in "apps.dev.microsoft.com" instead of the Azure Portal, etc. etc.

My head is spinning, and all I want to do is set a custom attribute on my Azure B2C user objects after they log in for the first time. Much more of this, and I'm just going to take care of authentication myself.

Has anyone else had a similar experience like this, or am I just out of my mind? Are there any concise and updated resources regarding this (seemingly simple) task that I'm trying to accomplish?