Can I disconnect an integration later?

Yes, and it's immediate: Settings → Integrations → Disconnect stops all reading and sending on that mailbox the moment you click, and removes the stored credentials. Revoking Monty's access from your Google account security page stops Monty renewing access from the provider's side, and any session already in flight ends within the hour. Your conversation history in Monty stays intact either way, so reconnecting later picks up where you left off.