You’re doing a number of things wrong,
In addition to the cluttered void loop and use of blocking delays, your dunkel and hell variables are being declared globally, then re-declared in your BLYNK_WRITE(V1) and BLYNK_WRITE(V2) callback functions…
the int command before these param.asInt() commands is re-declaring these variables locally, and preventing the widget values from being visible outside of the callback functions.
You should probably use lambda timeout timers instead of delays to implement the mark-space ratio for flashing your LED. See the “Timeout Timers” section of this topic for more info…
Pete.