I'm simply trying to add a label to a new page via v2 REST api. The documentation shows no v2 API that POSTs labels. All are read-only. The v1 api doesn't say deprecated for /content/{id}/label, but here lies the problem.
v1 references pages as "content" while v2 has almost entirely dropped the use of "content." ContentID does not equal PageID. My test consisted of using the page ID to fetch the content ID and then performing the v1 api label POST against the contentID. This gave me a 403 forbidden despite having full access.
Build new page. Use its pageID to get contentID
confluence_rest_api_url + "/wiki/api/v2/pages/ + str(pageid) + "/properties"
The result is in field "id"
confluence_rest_api_url + "/wiki/rest/api/content/str(contentid)/label
The POST body has the label structure: array of objects
403 error.