Zend certified PHP/Magento developer

Region select not showing in checkout after upgrade to Magento 2.4

Are in the process of upgrading from M2.3.5 to the current version of Magento – 2.4.3

However, after having done so the Region select dropdown no longer appears in the checkout (on either billing or shipping address)

Have dug through the database comparing eav_attribute, eav_entity_type, customer_eav_attribute & customer_eav_attribute_website settings on our upgraded store against a vanilla Magento 2.4.3 store where region picker DOES show, and I can’t see any difference.

Inspecting the code on the checkout page, I can see that divs for both region AND region_id are created BUT they both have display:none set inline (Checking the vanilla store, and region shows like this there as well.)

enter image description here

If I set display:block, then I can see a Region select, but it doesn’t have any option in it – I guess because knockout doesn’t see it on page load.

So, does anyone know WHY this field isn’t being displayed? Or have any ideas on where I can check to find a reason?

Problem occurs using blank theme, luna or our custom one and so isn’t related to that.

Thanks!