Your battery drains more the more you activity use the device. Shocking…

If it is your phone just uninstall those apps, then you cannot use them. If the devices main point is those apps like gaming on the switch what do you expect? I think the only real problem here is the switch’s lack of customizability so you have no trade off between game quality and battery life like you can on something like the steam deck.

It is a digital signage display (ie in store ads, menus, displays etc) - not meant for desktop use.

There is a native windows docker as well, where you can run windows containers inside it. But no one uses it, everyone just wants to use the linux containers which require a linux kernel and thus virtualisation on windows. Performance should not be worst on it though, but the layer of a VM added to it adds a layer of jank to make it appear to work like the native linux version (ie mounting host folders need to be mounted on the VM first before they can appear in docker, and while that is mostly transparent it can cause a few issues with some things).

Linux is fairly secure out the box and typically does not need any sort of extra hardening for most people unless you have a specific case you are worried about or some threat model that requires it. And hardening a system is not simply about installing some package, but more about learning to setup and utilise said packages to mitigate the threats you think you are going to be dealing with. Hardening a system generally comes with tradeoffs and these are not always worth the cost involved for what you get from them. All depends on what types of threats you think you will face - a journalist in a hostile country is going to want a far more secure system and will be more willing to compromise on other aspects to get that then some grandma that just wants to look at pictures on facebook. Both of these will want different tradeoffs for their systems.

Generally speaking I would start by reading up more about hardening linux systems, and what types of things these tools are designed to do. I would start with anything related to the system you are interested in, nixos has its own guides general security which links to many things you might want to think about. Arch Linux also has some good guides on security that are worth a read. And there is more general stuff like The Practical Linux Hardening Guide or redhats guides though these are more server focused and might offer tips that can be too restrictive for desktop systems.

As for apparmor and selinux, these are competing technologies and I don’t think you can use both at once.

Or a better idea: don’t use goto. In any language. Especially not one that needs line numbers to work and not labels, as soon as someone edits the file utter chaos will ensue. This has all the normal downsides of gotos with labels, but with far more downsides.