Hi,
It's almost guaranteed that it will be different, as Joomla API will quite likely have different mechanisms than WordPress. It's like payment gateways, each one of them has its own API.
The only way to have the same API as Woocommerce would be to actually not implement Joomla's API system by have a plugin made especially to mimic Woocommerce's API. And even then, the API is specific to Woocommerce, so some things can't be implemented the same way. For example, they have an API to get the settings of woocommerce:
woocommerce.github.io/woocommerce-rest-a...-all-setting-options
The settings are different in HikaShop and thus we cannot provide the same list with corresponding values.
So if your ERP needs that API, then it would be more difficult as we would need to know what settings they need to know to provide the adequate response in the API plugin.
Basically, us implementing the REST API of Joomla won't help you and if you need an integration with an ERP and you can't have a custom plugin developed between HikaShop and the ERP (if there isn't one already), then I don't see this changing any time soon.