Список репозиториев debian 12 Прописываем в /etc/apt/sources.list (плохая практика) Лучше создайте файл в /etc/apt/sources.list.d/debian.list

# From https://wiki.debian.org/SourcesList
#
deb http://deb.debian.org/debian bookworm main contrib non-free non-free-firmware
deb-src http://deb.debian.org/debian bookworm main contrib non-free non-free-firmware
#
deb http://deb.debian.org/debian-security/ bookworm-security main contrib non-free non-free-firmware
deb-src http://deb.debian.org/debian-security/ bookworm-security main contrib non-free non-free-firmware
#
deb http://deb.debian.org/debian bookworm-updates main contrib non-free non-free-firmware
deb-src http://deb.debian.org/debian bookworm-updates main contrib non-free non-free-firmware

Устанавливаем ключики

sudo apt install debian-archive-keyring

Обновляем кеш пакетов.

sudo apt update