awesome writeup Remie. I think this post pretty much described the frustrations of those affected including my team and me.
There’s a bunch of community posts seeking for more details on Media API in the past like these and I don’t think we got any support:
I also emailed the Media API team after stumbling upon a documentation page on using Media API - https://api-gev2.media.atlassian.com/api.html
(which has been taken down now) and was told that they no longer provide external consumers with the ability to use the API directly.
As for working around it, similar to yours - my team and I went with uploading files to page via AP.request
to /rest/api/content/${contentId}/child/attachment
directly.