Like as in beer? No. Or free as in freedom? Also no.
However, iCloud will give you a large amount of the feature set for a fraction of the price (starts at $0.99/mo) and will likely give privacy not too far from what Proton gives you.
In the end, there’s always a risk with putting any information on the web.
I would love to see something like macOS’s FileVault encryption. It completely blends in with the login screen and your decryption password is your user password.