Authorize.net has a new Api, which is not the old name-value-pair API.
This new API has some nested fields and things like that.
Do you know if Magento already supports this version or it will support it in the near future?
You can check the newest version for magento 2 at GitHub,
Check Magento 2.3 Develop branch from below link and check whether API Uses as new format or already exist.