Surgery is an effective way to increase fundamental frequency that carries recovery time and some risk.
There's 2 main types of phonosurgery that trans women get, a relatively simpler option and a more comprehensive one.
Glottoplasty
Aims to reduce the length of the vibrating part of the vocal cords, effectively creating higher pitch.
https://pubmed.ncbi.nlm.nih.gov/20171832/
Laryngoplasty
reduces size of larynx and voice box while also increasing pitch.