unfortunately when talking packaging and application deployments you really have to try the different methods till you find what works for your scenario.. even more so for an un-named add-in. Couple of my common options below
If .pkg you could just upload it and make a smart group for computers with outlook.app (just to ensure that installs before the add-in).
You could use a snapshot in composer to roll the outlook and add-in installation into a single deployment package.
certain installations with references outside of installation package you are copying a whole folder into the client's tmp folder and then using a script to run the installation from there
@aric_wallner You might want to check out this KB article from Microsoft regarding changes in support for injection based Outlook plugins if you have haven't already seen it: https://support.microsoft.com/en-us/office/outlook-for-mac-planned-update-for-injection-based-plugin...