You guys know I live and breathe this sport for decades now. Comaneci is not my GOAT either. She was excellent for her time, but anyone who knows a bit about how gymnastics is scored nowadays would be aware that her routines which received a perfect 10 score would not have received a perfect 10 in execution today. Of course, anachronistic comparisons are almost always very hard to do correctly, so it might be pointless to compare today's scoring sytem with the system used in the past, but if we want to determine who is the GOAT, these kinds of comparisons are inescapable. The whole "she's the first perfect 10 in history" actually masquerades what was essentially a completely different way to understand this sport back then. Of course this doesn't diminish her achievements as a gymnast.
There's a number of legendary gymnasts in this sport: Caslavska, Korbut, Shushunova, Boginskaya and Silivas; more recently, Chusovitina, Khorkina, Mustafina and, of course, Biles.
However, Latynina won medals in every event at a single edition of the World Championships and in a single edition of the Olympic Games. Besides, Latynina has 18 Olympic medals, something that Biles will probably never be able to achieve -- even if Biles wins every possible medal this year and every possible medal in 2024, she will still fall short, with 17 medals.