Hey @woutervb,
As @alexmurray this request is not falling under the supported categories for granting classic confinement.
Unfortunately no, the personal-files interface is typically used to provide read-only access to top-level hidden data directories within a user’s real home directory, in order to support importing data from existing applications where the snap is the clear owner of the target directory. But I think you could request the use of personal-files with write access to each of the tools which usually depend on curl. Do you think that works? If granted, it probably will need manual connection since curl will not be the clear owner of such directories.
For other directories, you could explore system-files or even system-backup