[3][5] Since the end of 2019, Efremova trained daily at the Mouratoglou Tennis Academy in the South of France under French coach Pierre Debrosse and the supervision of her mother.

[3][4][6] Efremova's father never lived in France, but visited his family several times on the French Riviera before his death from cancer in Germany in 2021.

[10] Efremova then leapfrogged to the ITF Juniors under-18 circuit, where she won five titles in categories grade 4 and 5, the first of which just nine days after celebrating her 13th birthday in April.

[11] In January 2023, Efremova reached the final of the Petits As in Tarbes, the world's leading indoor U14 competition, which she lost to Anna Pushkareva.

[14] In March, she reached the final of a U16 tournament in Torelló despite still being one month away from her 14th birthday, and although she narrowly lost it, Efremova did win the doubles events with Adelina Lachinova.

[16] In November 2023, the 14-year-old Efremova won her first WTA point after coming through qualifying at an ITF event in Monastir, and beating Camilla Zanolini, and the third seed Yang Yidi en route to the quarterfinals.