While I do not have the answer, I would like to bump this post and hope W&B could chime in with a solution.
I was also looking at deleting specific files from a run to keep within the quota, but also to avoid saving files that would never be used, e.g., models within a sweep that performed poorly.
The files are not logged as artifacts in my case.
Hope someone can help?
I note that there are other people requesting support with similar issues as seen in
[1] and [2]