Isn't this what the (mostly unseen) Temporal war in ENT was about? We saw various versions of Daniels die but he continued to crop up. That's cloning.Why doesn't the Federation use time travel to create Temporal Clones of its best ships and officers, during war time? What's stopping 99% of grief stricken people from using time travel to change fate? Why isn't anyone attempting to use time travel to cheat death forever? What reasons, other than "muh Temporal Prime Directive/Preserving the Timeline."
And Janeway did the grief thing in "Endgame"