Her series was serialized in a Japanese magazine where series might end very quickly if they rank low on reader’s poll, and Sailormoon was specifically ordered to her so that Toei can create an anime with its sponsor Bandai, so they can sell toys. Rules are kinda clear even if she was young at that time.
So yes, artistic freedom is great and all on the paper, but when you enter the manga/anime world, you have to compromise and it seems she had hard times doing this. Killing 90% of the main cast in Stars first chapters in a magazine aimed towards girls from 6 to 12ish was a weird move (even if it might be interesting from an adult point of view), and it’s hard to get why she didn’t understand that the anime didn’t want to use some of her idea considering the target audience.