What are some alternatives?
When comparing Let's Encrypt and OpenSSL, you can also consider the following products
FileVault - FileVault is a method of using encryption with volumes on Mac computers.
Ensighten - Ensighten provides enterprise tag management solutions that enable businesses manage their websites more effectively.
Microsoft BitLocker - BitLocker is a full disk encryption feature included with Windows Vista and later.
React Native - A framework for building native apps with React