Workflow for linking files and animating with actions

I’m totally lost. I thought I was making good progress, but then when I go to try things…nope.

I created a file with an object that has a door and an object that opening the door moves. I may update some of that data later (not by choice, but I’m trying to plan for it). I created the door opening as a driver, animating the other object. Although, that’s mostly because I couldn’t figure out how to animate two separate objects in one action. Every time I did, it seemed to automatically parent the second object. But that doesn’t really work for one object rotating, but the other translating.

So, have the door open action.

Now I test a new file. Link the collection, and even create a proxy for my door. Select the door, rotate, Yay, my driver came through fine. That object moves properly. Link the action.
Well, that’s odd, it’s not listed in the action editor, but it’s listed under Outliner>Blender File.

I had troubles creating an NlaTrack. I mean, that was a pain in the Butt. But I can’t find much help on how it works. There are a few examples, but they are more follow along type tutorials, not “let me explain how this system works” kind of tutorials. I didn’t know that the Nla seems to only show tracks for actual objects in your scene. But I was under the impression that it was closer to a video style NLA. So I selected the proxy door I made and hit new track. No, it wouldn’t let me. I had to click “include selected objects” before that, then create a track, Then add action strip. Where are the tutorials that tell you that!?!? And selecting my Door_Open action, I thought I could duplicate it on the same track, but it creates a new one? I am thoroughly confused.

So I guess I got it working? Is that actually the workflow?
So if I go back to my other file, and edit the door opening animation, it Should update here right?