Sell, no POST method to upload documents. Selenium alternative?

We migrated to Zendesk Sell at the end of last year but still have documents to attach to our legacy deals. I noticed there's only GET but no POST method.

Since we don't have an option, we're considering an alternative to automate the upload by using headless and Selenium Webdriver on the front end. Any ideas around this?

Only GET method on API

• https://developer.zendesk.com/api-reference/sales-crm/firehose/documents/

Complains about the lack of a POST method documented on the API

• https://support.zendesk.com/hc/en-us/community/posts/4913475572250--Uploading-Attachments-to-Sell?input_string=Sell%20API%20attachments%20documents
• https://support.zendesk.com/hc/en-us/articles/4408836479386-Attaching-documents-to-leads-contacts-and-deals