Perhaps, if I put my tongue in my cheek a little, the best solution is to call the Holy Spirit “they”. For some this will be understood as a singular “they”. But, to those who might object to the singular “they” or insist that it carries nuances of plurality, I point out the ancient Christian tradition of the sevenfold Spirit, based on Isaiah 11:2 and repeated references in Revelation (1:4, 3:1, 4:5, 5:6) to the seven Spirits of God. So there should be no objection to using an apparently plural pronoun to refer to them.