Windows or macOS provide easy ways to encrypt/decrypt the system drive (such as C:\ on Windows) whenever the user wants using GUI. It seems that the system drive encryption is an option at the installation GUI of Ubuntu, but there is no GUI to do it after installation, unlike Windows or macOS.
What if I want to encrypt it after installing Ubuntu normally? And what if I want to decrypt it after installation with the encryption option? Is that supported? I mean, without reinstalling the system.
There seem to be some tutorials about encrypting the home directory after installation, instead. So, on Ubuntu, it is recommended to encrypt only the home directory instead of the whole disk?