Use an apt cache for your network! It speeds up Linux deployments and upgrades substantially, and also reduces network bandwidth usage to the internet.
Since I am an avid Proxmox user, I use the simplicity of the community scripts to install Apt-Cacher-ng as an LXC container. See my The Stack page.
Along with this, you may want to install auto-apt-cacher and follow the advice to set up a DNS Service record in your DNS to make it more easily available. Once that is done, add the /etc/apt/apt.conf.d/00apt-proxy.comf file with the following:
Acquire::http::Proxy-Auto-Detect "/usr/bin/auto-apt-proxy";
Acquire::ftp::Proxy-Auto-Detect "/usr/bin/auto-apt-proxy";