Hi folks,
i've a workaround - working for me (dx11/w10) 😉 - i want to share.
If any of your small character icons on is loaded whilst the others don't and login-screen background stays black:
Pick the leftmost shown character and log in.
This results in the known infinite loading screen and i terminate the game ~30s later (wait a little, else the game does not put your picked char on the first in line).
After a new started game, the last picked char is the left in the line, loads and "chainloads" all other chars and then the login-screen background. After this i can login whith whatever char i want (until next switch ofc).
HTH