@State128: The problem is, the reference to the PlayerState doesn’t arrive in time for the OnPostLogin. My other problem was that the client also needs MyNumber instantly. When the normal variable replicating starts, it’s already too late, because some textures set themselves based on this.
In the end, this was the solution that works perfectly:
This way the client gets instantly the variable and sets it locally too, so every other blueprint can use it before the normal variable replication arrives. And also I don’t need to call the PlayerState’s init event on the client.