As described, we recommend strict mode and that the snap plugs home and removable-media which should cover all typical use cases. As for $HOME/.config/onedrive, this could be covered by personal-files (though please read through the linked documentation).
In addition to not having to be approved for classic, your snap will be installable on Ubuntu Core and be more reliable across all distributions (see ‘Caveats’ in Process for reviewing classic confinement snaps).