Really? You have a 5120x2880 monitor that macOS is messing up? I've never heard that before. Talk to LG, there's got to be something wrong with it.
>Auto-updates can be turned off on Windows as well. I still get updates I didn't expect on macOS, often when I've told it explicitly not to do so (like when you get the notification requesting it).
Not Apple's fault that you don't know what you're doing. I've turned off auto-updates and nothing updates unless I tell it to. There are some apps that auto-update on their own, like Chrome and Firefox. But they do that on Windows too.
> Regarding the headphones, it's a common issue. In our case, it was done when the Bluetooth headphones (a model sold in Apple stores!) simply connected, as another commenter mentioned.
Basically the headphones that do that send a play command when they connect. Apple will auto-start iTunes/Apple Music when nothing is loaded and play is hit. Yeah, that's annoying. I wish Apple didn't program iTunes that way, but that is entirely the fault of the headphones. That's why bluetooth headphones today don't do that.
I can also confirm that OSX doesn’t have a good case with external monitors, but I am no longer sure that it is possible at all. Frankly, all OSes suck at it so hard that one should just try to avoid the situation. Strangely enough the new Wayland on Linux may be the most adequate at it, though it is still far from perfect.
Regarding the headphones, it's a common issue. In our case, it was done when the Bluetooth headphones (a model sold in Apple stores!) simply connected, as another commenter mentioned. There's all sorts of forum posts about this with a litany of solutions. The only solution that worked for us was to rename iTunes (the name at the time).