If you want to try a different experience I would recommend fedora since its a distro that isn’t too much different to Linux mint which is good to prevent frustration in the long run, also the login menu has a option button that if you end up installing a different desktop environment or window manager its very easy to try it out without tinkering too much in the terminal.
If you don’t mind trying something different then I would recommend wetting your toes a bit into window managers, is different then desktop environments but it rewards you with more productivity in the long run if you don’t mind getting used to it. My recommendation would be sway or i3.
Each distro focuses more aspects then others, for example arch linux its all about control so you are going to have a lot more package variety but in exchange for having to know how to make each program work together by configuring them on the terminal and stuff, while for example Linux mint provides you with already a working environment that you don’t have to worry about it but in exchange you are not going to have the abundance of programs like arch naturally in the repos/aur. But in every Linux distro you can install everything including kernels if you wish to take time cloning git repos and using ‘make’ and configuring them to your liking. (Not to mention that some apps you can install setups online like VeraCrypt for example)
In regards to monitoring and killing process, I would recommend installing htop since it makes rather easy to see what is happening but generally speaking linux already provides tools for this with the default gnu packeges that come installed, and one of those is top which is the barebones version of htop (htop is better imo but you can try it)
For installing you want to flash a pen with the installer iso of the distro you choose in their website in the download section, then connect the flashed pen to the computer and reboot it to the bios, when you are there make sure you can boot into USB devices cause secure boot doesn’t allow you to do that, after disabling secure boot select the USB drive as the first device to boot from in the bios. After that its just saving the bios settings and booting the device normally and you just have to follow the installation guide provided by the distro. Make sure you save your files before installing a new OS, its going to wipe the data.
When it comes to installing stuff from the repos there isn’t really something you should avoid, its on the repos cause its trustworthy software otherwise you are going to see it elsewhere like on the aur and other places where its easier to post software and cause of it you shouldn’t install everything you see there (aka do always research before installing from these places).