[dynamictext inputname “CF7_get_current_user key=’user_nicename'”]

Hi everyone,
I am trying to get the alias or first or last name of the user through the plugin but I always get the username value.
I am using these shortcodes:

[dynamictext inputname “CF7_get_current_user key = ‘user_nicename'”]
With this it gives me the username.

[dynamictext inputname “CF7_get_current_user”]
With this it gives me the username, exactly the same as the previous one.

[dynamictext inputname “CF7_get_current_user key = ‘ID'”]
With this it returns the user ID.

[dynamictext inputname “CF7_get_current_user key = ‘user_email'”] With this it returns the email of the user.

I don’t understand the difference between the first two, or why the “nicename” attribute exists.
Can you help me get some other value from the user?
Thanks!