Is there a difference btwn login items and startup items

additionally, just as an FYI, the more login items you have, the slower your startup process. Considering today's quick app startup, there is really no reason to have any items there, they will launch in a split second when you want them. I have none in my startup items.

Those links are from 2013. If you have any startup items, it doesn’t matter if you remove them or not. They won’t work. The only concern for them would be to update any software that uses them. Otherwise, that software might not be working correctly without its startup items.

Login items are even more tricky. The login items that you listed in your first post are also effectively (but not officially) deprecated. They will still work. But there is an entirely new category of Login items available in recent versions of macOS. These login items are not shown in any user interface or even any low-level API. They are hidden and very difficult to find. My own app EtreCheck can find and list them. One of Patrick Wardle’s apps can do that too. Those are the only two tools that I know of at this point that can list modern login items.

Startup items were deprecated years ago. They don’t even work anymore, even if you have them installed.

Startup Items affect all users on a Mac and start on startup. Login Items affect specific users and open when they log in.