Is there a way to start a sync with cron or hook?

Hello! We are syncing products from an external system and uploading product images via restAPI. The problem now is that product images are automatically uploaded to the server. I need either a way to upload them to GCS (preferably) and automatically start a sync so that they will be uploaded in the media library statelessly, or upload them to the server but immediately trigger a sync so that they are removed from the server and uploaded to GCE. Can you see any ways to do this either through cron or a hook to your plugin?