Are extra fields added with hook_entity_extra_field_info(). not available on product variation pages?

Is it generally impossible to render an extra field on product variation pages, because of how the variant fields are injected into product pages?

I added an extra field to the product variations with hook_entity_extra_field_info(). and I see it in the "Manage Display" Tab like it would appear on any other entity. But I can't output it. It is simply not available in the theme. If I do a {{ dump() }} in the product variation template it is not listed at all.