Because that isn’t what that property is actually for; it’s for the domains for which you want to obtain a cert, and once again goes back to the old days with dehydrated.
You already found the topic from April (since you posted there); surely you saw my PR linked there? Lets Encrypt renewal the 105th - #8 by danb35
Yes, that’s what ought to be done. Get rid of the script, obtain certs with the --post-hook, and run a daily certbot renew.