I'd say Tied By Fate would be better than Red Strings because it's not as used. If you search it up on AFF you only get two stories with the same title, but if you search up Red Strings it brings up several pages of fics with the same name. And a more original title like that tends to draw in more readers. I personally would be far more intrigued by Tied By Fate than Red Strings, but that's just me.