The issues that arise from systems assuming the sex binary is real and absolute - IGM, medical care failures, and so on - are very tangible harms.

You yourself here refer severally to “sex differences” that are contentious or mythical - including the idea that heart attacks have different symptoms in men and women:

https://www.bhf.org.uk/what-we-do/news-from-the-bhf/news-archive/2019/august/no-difference-in-key-heart-attack-symptoms-between-men-and-women

I don’t think it “Orwellian” to point out that assumptions about what is “obvious” can be deeply harmful.

Assuming binary sex difference exists where it does not has been and remains the basis of a lot of misogynistic myths (as well as homophobic and transphobic ones).

I explicitly tackle the “who deserves what” issues elsewhere.