I always assume that anything I send unencrypted through any cloud service is archived for eternity and is not private.
Not your computer, or not your encryption keys, not your data.
Even "your" computer is not your own. It's effectively controlled by Intel, Microsoft, Apple etc. They just choose not to use that power (as far as we know). Ownership and control are not the same thing.
It’s a question of degree. The cloud is at one extreme end. An air gapped system running only open source you have audited is at the other extreme end.