There is an app in development for OneDrive at least: https://github.com/hevelius/files_external_onedrive
See discussion here: Integration with OneDrive
For Google cloud: Support to Google Cloud Storage?
However most of us use Nextcloud to get away from these providers, hence the low priority this obviously has. Also I am not sure how easy or free-to-use Google/Microsoft etc develop their APIs. There was ownCloud OneDrive support once but broken due to changes, probably those providers do not want to make it too easy to implement their clouds access to any other client, to force using their own ones?