Female incels do exist but don’t have the same problems as men, for the most part. Female incels are generally those who are dissatisfied that they are not in the top 20% of women and want top 1% (or above) men and can’t get them. They easily could be with other men but do not desire them.
By contrast, male incels are angsty about the fact they can’t even catch the attention of bottom 20% women. This is what happens when you’ve structured a society where 80% of women are competing so very hard for the top 10% of men.
Note: I am not an incel and never have been.