1.) EndeavourOS is meant for intermediate users (I’m sure you are one with many many years of experience)
2.) Please try to avoid package managers, preferably use a terminal. IF you must use a package manager, consider octopi or bauh
3.) Try in a VM/Boxes for a while to get a feel for the distro. Install your favorite apps/themes/settings and from there start asking any questions that may come up
4.) Make sure the Arch repos has all the software you want first. Also check the AUR for packages. There’s always flatpaks/appimages/etc if you need
5.) IF you have Nvidia hardware, you’re going to have some questions… (I’m an Nvidia user myself, so there is a bit of a learning curve, but it’s very doable! most of us here are happy to help)
6.) IF you don’t care about filesystems, sticking with Ext4 by default is just fine, fyi.
7.) It’s a good practice to have at least two kernels installed in case one has issues. EndeavourOS has akm
to manage install/uninstall kernels. I use the mainline and LTS kernels. There’s also the zen and hardened kernels to use as well if you wish
8.) In regards to the AUR, it’s unsupported, so please use it at your own risk. What I mean by that is only use the AUR when you have to, don’t treat it as just another repo. While it’s generally safe to use, once you know more about PKGBUILDS, it can serve as another tool in your toolbox.
9.) A good brief read from the wiki to give you a feel for what Arch is and isn’t: “Arch compared to other distributions”
10.) One easy way to learn more pacman commands for the terminal is Pacman Rosetta, it shows various popular commands between a few other distros so you know the apt upgrade equivalent for pacman. A must read in all honesty.
If you have the time, the patience, and the desire to learn, I’d say give EndeavourOS a try and feel free to ask any questions here if you get stuck. Plus there’s lots (aka too many!) Plasma users here, so you’ll be in good company. Lastly, welcome to the forums @slewin