>>> Is this an issue with all cloud providers? Or just large ones like Google, Amazon, Microsoft? >>> I'm currently thinking of migrating from Google for productivity to Office 365. Wondering if I'm just re-branding the risk of my counterparty.

With AWS/Azure, you typically wouldnt have extensive personal data with them, so you dont have the risk of work and personal accounts colliding. I dont know anyone with personal emails/accounts/photos on the Microsoft ecosystem. With Amazon, whats the worst that can happen? You lose your connected Amazon purchasing account, doesnt seem terrible.

With Google you often have email/documents/photos with them. If you have an Android phone, you have almost everything with them.