some ways to find out debian version:
root@pom:/etc# cat /etc/issue
Debian GNU/Linux buster/sid \n \l
root@pom:/etc# cat /etc/debian_version
buster/sid
root@pom:/etc# cat /etc/os-release
PRETTY_NAME=”Debian GNU/Linux buster/sid”
NAME=”Debian GNU/Linux”
ID=debian
HOME_URL=”https://www.debian.org/”
SUPPORT_URL=”https://www.debian.org/support”
BUG_REPORT_URL=”https://bugs.debian.org/”
root@pom:/etc# lsb_release -da
No LSB modules are available.
Distributor ID: Debian
Description: Debian GNU/Linux testing (buster)
Release: testing
Codename: buster
https://linuxconfig.org/check-what-debian-version-you-are-running-on-your-linux-system