This is the guide I followed when I was installing Arch manually. I hope the method has not changed. Make sure to choose the correct partition if you’re planning on dual booting.
For foss apps, I mostly allow analytics to track to help the dev out more. Complete 180 for any big tech since whenever they ask for it, they sell that information to the highest bidder.
Aktually, I prefer Arch + KDE. I say if you like your current desktop, then stay with it. I’ve hit the sweet spot with what I’ve got because I love the AUR, pacman, and paru.