where do i find the full list of startup items on a mac

Hi.

There are very many items that macOS runs at startup, including the items on the User Login Items list, most items are OS related launch daemons and launch agents. It's neigh impossible to produce a list of all such items.

Is there something in particular that you're looking for or are concerned about, a particular app or apps, for example?

Run an app called Etrecheck.

etrecheck.com

that gives a good analysis and also contains a full start ups list.