1.Theres dash to dock extentions to make it have a task bar like windows or mac, aswell as wigets for the top bar.
It is mostly true, some obscure laptops dont have everything working out of the box for alot of distros. And require lots of tinkering with drivers and kernel modules.
3.if you want to go ultra bear bones, theres alpine linux thats alot like android, but doesnt run android and is usally used for network appliances. Aswell as arch linux which installs base packages and is completely bare bones.
Then theres the manual side of linux There gentoo which is a source distro, meaning everything is built from source code and must be manually enabled and setup. Its great for low power hardware but you need to read alot of documents on the wiki.
Then theres the F all Linux from scratch, It is what you think.
Usually you need root to uninstall, packages unless its flatpak.
5.No root is the first account made on your system without root being made nothing would work its the equivalent of system 32 for windows.
Switching DE is super simple. Find which one you want in your package manager and install that package. After that when you get to the login page it should show up in the sessions tab or gear icon for gnome. And simple select your DE and login.
Wayland is a new display protocal that fixes and improves on previous technology such as x11 and xorg. Docker is Containerization The best way to explain it is. Your main distro is a truck and a docker container is having a linux distribution in a box. Docker containers are usually purpose built for services which run a preconfigured distribution for that purpose.
Also no problem helping out other, we all gotta start somewhere!