Recently i've been stuck on one part of a map that i want to complete, yet always die on, is there a way to practice a specific part of a song without using editor?
Depends, you definetely shouldnt retry the song and trying to do it somehow, you will most likely get mindblock that you wont be able to break for a long time. If its for example square jumps I suggest downloading training beatmaps for it. Or simply move on and come back to it later
I don't think there is a way without editor, but why you don't want to use editor? Making a new difficulty and deleting all notes before the part you want to practice seems easy enough