You can use Linux without a terminal, but life is so much easier to just remember few letters (command) and pressing enter instead remembering 200 places where a setting is. You can also always just do sudo pacman --help.

You can print any layer height that your nozzle allows, but on a 1.75mm filament I think 2mm nozzle is the max you can do (haven't seen bigger nozzles) At some point when your layers and prints get too big, you want to look at hotends that use pellets.

Looks like a clog, could be caused by too much retraction, too high temp combined with too low print speeds resulting with the filament being cooked inside the nozzle.