@eRRoR_DJ_Exe_eRRoR
Well, from my personal experience, i think it is best to discontinue a story if you have no interest in it any longer, or don't have the means to keep working on it. However, I also think just keeping it unpublished is fine if you plan to get back to it at a later point in time!
Also, about starting a new story, I think you definitely could! But if you're already managing other stories in the meantime, it may be best to just start the new story as a draft, writing draft chapters whenever you get inspiration, and when it's time, publishing the story chapter at a time!
Hope this helps! ^-^