Notion employees are only allowed to access your workspace data with your written consent. We are also only allowed to do this in order to facilitate an improved user experience for you (e.g. debug problems you have asked support about, etc).
We are working on updating our T&C and Privacy Policy to make this more clear, but it is rigorously practiced internally already.
We do not yet have end-to-end encryption, or other encryption functionality that would make it technically impossible to access your data. We would love to do this at some point but it will be difficult because our permission model is quite complex!