I know everyone will say Serena, but if someone wants to say Simone Biles was the best female athlete the last 10 years, I wouldn't argue with them. I know the sports aren't the same, so it's tough to compare.
She wasn't only just dominant though, she was innovative. Her jumps literally broke the rule book and were banned.
At Serena's prime she was still somewhat beatable, at Simone's prime she was basically unbeatable. Nobody could match her jumps because nobody bothered to practice them as they were that crazy, but she didn't just do them, she got them into her muscle memory and automatic. Probably the best Gymnast of all-time, male and female. In fact, one of the most dominant athletes of all-time for any sport.
I remember reading somewhere they literally rated the jumps she does so high because they don't want anybody attempting them for safety reasons. Again, she doesn't only have those jumps as a one-off, she has them automatic.
en.wikipedia.org
At 4'8 Physics tells us she can spin/turn quicker than taller gymnasts, but she's additionally insanely explosive.