Did you look into Scrypted? It is OSS. With HomeKit (which is how I use it) it is also E2EE. I’m not sure if their app is E2EE though, I only use HomeKit.
It’s pretty good and has an extensive ecosystem. The dev can be a bit… feisty though.
It’s very performant and easy to setup. I don’t use the NVR features as I already have an NVR, I essentially just use it for HomeKit integration of my cameras + doorbell.
As much as anyone can say otherwise, running Linux isn’t just a breeze. You will run into issues at some point, you will possibly have to make certain sacrifices regarding software or other choices. Yes it has gotten so much better over the past few years but I want my time spent on my work, not toying with the OS.
Another big selling point of Apple is the hardware. Their hardware and software are integrated so seamlessly. Things just work, and they work well. 99% of the time - there’s always edge cases.
There’s solutions to running Linux distros on some Apple hardware but again you have to make sacrifices.
It also works when using Spotify Connect on your iOS device. If you can use your volume buttons to control it you can also adjust it with the slider in the control centre.
I use modified IPAs of any apps that serve me ads. It’s always weird when I use / see these apps on others devices and notice the amount of ads that get chucked at them.
I’ve been using macOS as my primary development environment for the past ~4 years and have loved every minute of it. I haven’t run into any of the issues you’ve mentioned thankfully, and docker works absolutely fine for my use cases. I can’t see myself ever switching for any reason.