May I present my solution to this called
StripCharts which you can run on your truenas scale box without consuming many resources:
It's a simple dockerized cron script that grabs just the specifed apps from the TrueCharts catalog and pushes them into your own github catalog. You have to provide these environment variables:
STRIP_STABLE to specify the stable apps to grab, e.g. nextcloud|plex|traefik|cloudflareddns|vaultwarden (it's important to separate via pipe | because that is directly used inside a grep regex)
STRIP_INCUBATOR to specify the incubator apps to grab, e.g. actualserver|breitbandmessung-de
STRIP_REPO to specify your git repo URL where to push the stripped down catalog. I recommend github because you can host a repo for free and you can include the auth token to authorize the push, e.g. https://ghp_17613457614573562476235476@github.com/tuky/my-stripped-charts.git
The script will always amend and force push on the last commit (or create a new commit, if repo still empty) to prevent the repo from getting larger in file size.
Contributions welcome! thx