There is a setting under Settings for Addon-Management.
Choose whether to download add-ons when they are installed or use a locally stored collection of all the add-ons.
I am not sure if such happens if the Access Remote Repository is switched to off with no addons stored locally.
Hmm, are you sure we talk about OH3? There is no such setting in OH3.
But I found out something else, I started my backup-Pi which runs a backup about two weeks old, on this Pi the missing section is available. The Menu entry “addon management” on the right is also missing on the production Pi.