We are looking for advice / best-practices / caveats about migrating off BIND on to Unbound https://nlnetlabs.nl/projects/unbound/about/ for internal & external (customer-facing) DNS. Is unbound suitable for this, or is it only recommended for caching? How easy or difficult is it to move 10000's of existing BIND DNS zone entries? We already use Amazon Route 53 for our AWS instances and Cloud DNS for our GCP ones, but would like to maintain internal DNS for cost, control, and latency reasons.