Screen starting to flicker before the bootloader downloads

What have you tried: redoing the flashing via etcher instead of rufus.

What is the error: When i try to install kali onto my laptop it runs smoothly till the select and install software part, once that finishes the screen will start flicking.
when i press ctrl + alt + f1 it has an error message that says

Bail out ERROR: ./src/modules/frontend/gtk/choice_model.c:146:cdebconf_gtk_create_full: assertion failed: (0 < count)
Aborted
(EE)
Fatal server error:
(EE) Could not write pid to lock file in /tmp/.tX0-lock

What device is this on: An Asus Laptop with an i3 6006U, HD520 Graphics

install it with the default software and don’t add any extra, wait until a successful rebooted system, and then you can add any extra software repos later in Kali tweaks.

Flickering sounds like a graphic driver issue, leave any updates also until its rebooted, and then see what it wants to install, you may have to configure it yourself.