If data can always be recovered no mater how you erase it (correct me if I'm wrong), is it possible to encrypt the data before saving it so that an unencrypted part of it is never stored? Let's say a text file.
[Xubuntu 20.04 LTS | live USB]
SnapOverflow
What are your goals in encrypting your data?
The Ubuntu installer offers an option to encrypt your Ubuntu installation, using a technique known as "full disk encryption". When you boot your computer, you'll need to enter a passphrase that is used to decrypt the key that is used to encrypt your filesystem. If someone steals your computer, or your drive, and it is powered off, they'll need the passphrase before they can access your data.
If your concern is what other people on the system can see while it's running, then full disk encryption may not help much: but using file system permissions correctly can help keep non-root users from your files. Encrypting your files with gpg or other tools may help, in case your permissions settings aren't correct. However, working with gpg or other tools for this case can be a bit exhausting: it certainly isn't as easy as one passphrase at each boot.