Answered by Shaykh Yusuf Weltch
Does long armpit hair or pubic hair affect validity of ghusl?
In the Name of Allah, the Most Merciful and Compassionate
Long armpit hair or pubic hair do not affect the validity of ghusl as long as one is certain that the water reaches the skin. However, it is the sunna and teachings of the Prophet, Allah bless him and give him peace, to groom oneself.
The sunna is to trim the nails, pluck the hair of the underarm (though it is allowed to shave), to shave the pubic area, and the mustache (although trimming it is better). [Mawsili, al-Ikhtiyar fi Ta’lil al-Mukhtar]
Hope this helps
Allah knows best
[Shaykh] Yusuf Weltch
Checked and Approved by Shaykh Faraz Rabbani