

Linux is a worldwide community project, and its source code is readily available. It’s nonprofit. Proton is now a Swiss nonprofit organization without shareholders (https://proton.me/foundation). Nextcloud is an open-source project that you can host on your own server or in the cloud, which means you have total control over your information.
These are nonprofit projects that don’t seek to monetize from you because you’re not the product.
There could be multiple factors. For example, I have a Nextcloud instance that is fully managed by Hetzner, and I didn’t bother to find out what database it uses…