Anonymise Customer Data in GraphQL

I need to Anonymise Customer record IDs via graphQL API, the Shopify support recommended the customerBulkAnonymize and customerAnonymize methods however neither of these appear to exist on the graph QL API.
Has anyone been able to achieve this using graphQL, and if so could you please recommend what methods you used? Searching the Shopify dev docs I could only find details on customer erasure which we don’t want.
(A 3rd party app is not an option either).