ASIM parsers in Microsoft Sentinel are stored and deployed as YAML-based content files following ASIM schema templates (e.g., DNS, NetworkSession, etc.).
When you have multiple custom parsers (200 in this case), the most efficient way to manage and deploy them is to create a YAML file that defines all parser configurations and then import it into the Sentinel workspace.
YAML is the supported format for ASIM parser templates in Sentinel's content hub and GitHub deployment model.
Hence, the correct first step is to create a YAML file based on the DNS schema template.