As I understand it, the current PC protects both transitioners and detransitioners from discrimination if they need time off for medical appointments etc.
If it is removed and protection is belief or gender expression, I don't think this would provide the same protections.
For belief, detransitioners could miss out because many no longer believe that they have a gender identity. And gender expression wouldn't cover either transitioners or detransitioners for medical appointments. Also it might have the unintended consequence of letting Málaga Airport folk wear all sorts of weird stuff and claim protection under "expression".
Either keeping gender reassignment or putting under disability could work, but the latter would require gender dysphoria to be recognised as a mental illness. I would be happy to keep the PC of gender reassignment as is if sex in the EA is confirmed to mean biological sex, irrespective of GRC status. It'd be even better if the GRA was also repealed.