Good afternoon.
As far as I can see, in the API for issuing settlements of Novaposhta
https://devcenter.novaposhta.ua/docs/services/556d7ccaa0fe4f08e8f7ce43/operation... the areas are not correctly filled everywhere - and therefore I cannot guarantee the correct result.
The region is in the SettlementRegionsDescription parameter of the issue, but it is only in the 1st language and is not always correct (it may not be equal to the locality, region, etc.)
If you need it critically - I can analyze the issue by settlements - if the data there is more "adequate" - evaluate the appropriate revision.