Please show sufo lsblk -f sudo fdisk -l

Well updates installs not only security patches but also new features and there always possibly that something would break,so better if u would do upgrade urself manually

Well I would not enable auto updates to not get any random problems which can happen sometimes

About msg format https://support.mozilla.org/ru/questions/1257035 Thunderbird can handle them

Watch pdf files on remote server using ssh without gui