Perhaps CryptPad fits your needs. It’s an open-source privacy-aware collaborative office suite and storage solution. It’s end-to-end encrypted, so even if it gets hacked no usable information is leaked.

And since only Google knows it strengthens their data monopoly even further, as if it wasn’t bad enough already.

Depends on whether it’s skimmed. Your heart and arteries will thank you.

A bit of clarification about the quantum might help calm your nerves: to observe something means something such as light must interact with the particle you try to observe, and that very interaction changes the result of the observation. It collapses the wave function, and what you observe is just one of the possible outcomes. It’s not as crazy as you may think, but it’s very understandable that it may at first seem magical.