I suggest to check out the systemd article in the arch wiki and troubleshoot. There is a process still running that avoids your system to shut down. You need to figure out which one.
This is a natural behavior, sometimes the shutdown lasts for a certain period of time, usually no more than two minutes. The long press of the shutdown button should only be used as a last resort, as it may cause the file system to crash. During the shutdown process, in the virtual terminal, according to my memories, the remaining time until shutdown was visible. Check this out.
No it’s not… The EOS devs provide this distro and support to run and install it for free. They don’t provide hardware support (in the sense that they cant change code to make each hardware work). Either the drivers are implemented in the Linux Kernel, or if proprietary, some drivers are provided in the AUR, and others need some special settings. Other problems like the sleep mode in bios is a stupidity that was driven by windows and is up to the laptop vendors to implement or not. We can’t really change code in their bios.
In most cases, as Linux user we need to do some homework before purchasing hardware as not every drivers are available. Else fixes might be needed. I know it is annoying but I guess the little sacrifice to pay to get awesome open source operating system and software for free.