Downloading postinstall updates once for multiple builds

Ask Fedora
1

If Im doing multiple F38 builds, instead of downloading that huge batch of initial updates over and over each time, can’t I just download them once to usb and have future builds first “dnf update” somehow use them?

2 
# Runtime
sudo dnf upgrade --setopt keepcache=1

# Persistent
sudo dnf config-manager --save --setopt keepcache=1

See also: keepcache, cachedir, default cache location