some of those aspects are mutable (eg breasts) , some are immutable (eg genotype). Sex (male or female) is based on the overall picture.
Again this is incorrect. A woman who has had her breasts removed is still a woman. It makes no difference to her sex at all. None. The argument is illogical: breasts and secondary sexual characteristics are just that - NOT sex itself.
Woman has double mastectomy for cancer - still a woman
Woman has double mastectomy as part of transition process - not a woman.
Both those statements cannot be true. Removal of breast, ovaries, does not alter the sex of a person. That person is still female.
I’m glad to see you accept that genotype is immutable. Because that IS the determinor of sex. It is coded into every cell at conception. It cannot be changed or altered, regardless of what is done to the corporeal body with hormones or surgery.
Sex is NOT based on the overall picture. That is a profound misunderstanding of what sex is. Gender presentation maybe you can argue is more to do with how an individual sees themselves but sex is immutable. It cannot change - nothing can change it. To change it would require rewinding to the single cell stage and switching the chromosomes. It cannot be done.
Humans cannot change sex.
Everyone should be able to present how they want and be free from gender stereotyping